I finally was able to test out my new truck with a trip to Durango Colorado from Albuquerque New Mexico. I am impressed over all but have one concern. I was pulling the hill towards Purgatory with my 5th wheel in tow, following my buddy who has an 01 dmax and 5th wheel. I kept up no problem with the AC running. Suddenly, the engine temp started rising up, I shut off AC and kept pushing. The temps came down, but it went up to 230 or so. It did it again on another hill with outside air temp about 95. Maybe I am being to picky, but I never had my engine temp gage even move on my Ford. I have 2500 miles on and am planning a trip to San Diego, should I be worried? I need my AC.

Did you hear the roar of the fan when the temps started to climb. Its an obvious increase of noise coming from the engine compartment. I pull a heavy trailer out of the Phoenix valley with the AC running constantly (I have an '02) and never see those temps except when the ambient temp is in the 100+ with a 4-5 mile 6% grade. Soon as I top out the temps drop within a 1/4 mile to -200.

The fan clutch engages regularly, but the temps don't normally go up. I have plenty of coolant. I checked that when I got back. I guess I have to go without air on big hills.

Suit yourself, but I never do. Living without AC is like living without sex, it can be done - but not a good thing! Lifes little pleasures do count for something!


If you are seeing that much of a temp increase I would take it in to the Service Dept and have it checked out. I don't see that kind of temps on interstate pulls and I don't remember seeing much over about 200-210 even on the longest hills with 100+ temps. Have you tried to increase RPMs by using the O/D Lockout or manually shifting to 3rd, if your speed is within the limits of that gear.


Can you force it by heading east out of Albqu on the interstate? Mash it and force the speed to the limit +5 or more. Pulling your trailer should be able to see if the dealer fixed something.

I think that the only way I can duplicate it is with the 5th wheel behind it. The temps only go up when I downshift and push it with the trailer. Since this is an LLY, I was hoping others had the same symtom.

Maybe I am being to picky, but I never had my engine temp gage even move on my Ford.


Ford temp gauges don't work http://www.dieselplace.com/forum/smileys/HiHi.gif

It would move as it warmed up, and then it stayed put. I need to know if I am going to have problems on my way to San Diego.

After you get 10,000 miles and loosen the motor up some more it will not get that hot. My truck did that at first. Same hill, 10,000 miles later it did not get that hot.

exford,
did you hear the fan all the time when the temp went up? This is a fluid coupling design, the fan will be locked to the pulley if the temp is high enough. It will stay locked until its cold again. If the temp rises that high the fan should stay locked all that time!
Some folke on this forum are having problems with the fan engaging without any obvious reason, you seem to have the opposite problem. Is there a chance that the "clutch" design is not working that good (i. e. to much of a tolerance in the fluid coupling setup)?

Maybe I am being to picky, but I never had my engine temp gage even move on my Ford.


Ford temp gauges don't work http://www.dieselplace.com/forum/smileys/HiHi.gif





All of Fords gauges are switches. No movement. Either made or not made.

When the temp was rising, the fan was engaged the whole time. What do you think is a problem temp? It normally runs about 205 or so. On these occasions, it gets up to 225 or so. For the guys who think that it is engaging too often, is the switch a thermal switch or electric?

The fan clutch operates thermally, based on the tempurature of the AIR exiting the radiator.


I think that because of the EGR (Including a cooler in the recirculated exhaust stream) and Variable Geometry Turbo (which intentionally increases exhaust back pressure to drive the EGR flow) the LLY has significantly higher cooling loads than the LB7. The radiator didn't grow, so the coolant in it is generally hotter, transferring more heat to the air. Also the exhaust gasses added to the charge air in the intercooler means the I/C transfers more heat as well. Together these effects cause the fan to run more, and leave less reserve capacity for climbing the big hills. The LB7s with California Emissions for 2002 and later also have EGR, and have been reported to run hotter than normal on long hot grades. My LB7 without EGR can pull a 5th wheel west out of Denver up I-70 at temps above 100 degrees with the A/C on "meat locker" without ever hitting the 210 mark on the guage, but the fan does howl under those conditions. It'll do it at 68 MPH on cruise too, and it's so stock it still has the factory air in the tires. (Well, not quite, but it is stone stock).

Wonderful Explanation! That's what makes this site the best!http://www.dieselplace.com/forum/smileys/Clap.gifhttp://www.dieselplace.com/forum/smileys/Clap.gifhttp://www.dieselplace.com/forum/smileys/Clap.gif

I too have a overheating duramax it seems that pretty much all of the 2nd gen motors do! I have been complaning about it since it purchased it! Finally GM admits that there is a problem and they are not sure how to deal with it ! They normally get hot when you really use them with pullin around 18000 lbs.or so! At least thats what gm says the general weight they start overheating at! I had to go weigh my truck and trailer to get them to at least comit to any help whatsoever! My combo is 18560 total and GM says they will pull 20k so they have a problem with me! I suggest you go see your local dealer and have them call there tech line so that you can document the problem early on incase you decide to lemon the truck!

Is it time to petition GM, and have them TSB us the new electric fan setup showing up in the 05 trucks?

I am not sure the electric fan will do any good according to my dealer he says it needs a bigger radiator but there is no room in the 04 for a larger unit! the 05 has a 30% larger capacity he is told! Maybe a extra radator could be added somewhere ?

This might be kind of a temporary fix, but what if you drained the factory coolant and put in a mix with more water and less antifreeze?


I know that antifreeze does not exchange heat very well. If you're living in AZ or CA you might not need coolant that tests to -25 F.

Even running TTS extreme program pulling my 8500lb boat my engine temp won't move.. i've never see it go over the standard running mark.. i have heard of several LLY's that did this and think it may be something you have to live with. i wonder if anyone has had this problem running a TTS tow tune or edge on a low setting? wonder if the extra timing helps?

I just got back last night from a 2500 mile trip from Mesquite, NV (an hour North of Las Vegas) to the to the redwoods in CA. SEVERAL times my truck starting getting hot only towing a 8000 lbs trailer. At a couple of points the engine temp got up to around 230 and the tranny gauge up to about 210. It seems as if when either the the tranny reaches 200 or the engine reaches 215-220 the clutch fan comes on. The problem is that the fan STAYS on until the tranny drops below 200 or the engine drops below 215. Sometimes the fan would stay on for 15-20 minutes. The fan was even coming on on straights and downhills!! By the way this all happened only when in 95+ weather. My big concern is what if I was towing a 10-12K 5th wheel?! Not sure if I'm real happy with my $40K+towing vehicle at this point.

You know, I've been reading around on this forum and I can't recall where I read it, but GM is aware that there may be insuff cooling in the LLY. So much so that if you read the latest scoop about the 2005s, it clearly talks about updated cooling systems. Now I can't say for sure they were specifically talking about the LLYs (I doubt they were), but it would seem to indicate that GM is aware of the cooling issues. Not sure what that exactly means to the '04 LLY owners.

I finally got results from G.M.today and found out that there is over 800 open claims about the 04 lly duramax's about overheating problems with them it happens only when towing up a incline or a grade at higher ambient temps around 95-100 deg f. and they are issueing me a buyback on mine since they have no fix for them yet and apperently they are at a loss as how to fix them. My only question is do the 05 models have the same problem? Or do i buy a ford of dodge?

As I said earlier, it looks as if GM has re-eng the cooling...I say this based on what I read in the offical GM press release.

Not sure how you did it, but nice job on the buyback...those are NOT easy to come by from what I understand.

Silvertwinkie,
With the slippery shape of your safari ss, I would expect / hope you shouldn't have to worry about overheating a dmax. A 5th wheel is a different story. ( front surface area = drag ). luke
ps - I lurk over at airstream forums a bit!Edited by: luke warm

You are very right on there. However, if the cooling is underrated, it could still pose a problem on trips to Colorado or other mountain areas. Additionally, I may also in a year or so, upgrade to a larger (heavier) Airstream, so there is where my concern is at. I myself am not too worried, but I would like to see what they've done to the 2005 in what they talked about in their (GM's) press release about updated cooling systems. Do you have an Airstream Luke?

This might be kind of a temporary fix, but what if you drained the factory coolant and put in a mix with more water and less antifreeze?

Not sure that would be a good idea. That would lower the boiling point of the mixture and now your more likely to boil over. A 50-50 mixture boils at 265F, if you lower the antifreeze percentage you will lower the boiling point. I would leave at 50-50.

Jim

I just got back from a trip to San Diego from Albuquerque. I put a total of 2200 miles on the truck. I was towing a 5th wheel that weighs about 10,000 lbs dry. With all of our stuff and water I figure about 11,500. The truck wieghs about 7100 lbs. Total weight, 18600. I averaged 9.4 mpg according to the DIC. I have absolutely no complaints, but... it did get hot several times. Any steep hill longer than a couple of miles would get the gauge moving. I only had to shut off the air twice, but I am not happy with the over heating. This is brand new. What happens after 50,000 miles? I am going to talk to the dealer today and will let you all know what happens. I don't know what they can do. I don't want a buy back, I just want it to cool better.

As I understand this GM found out (one way or another) that there is a problem with the cooling capacity of the 2004.5 LLY setup. I assume thats why the 2005 has a wider cooler and a hood scoop.
This means also that the 2004.5 LLY DOES NOT work as specified by GM! I you buy something (anything) and the seller warranted a certain characteristic (in this case the max. trailer weight) the seller has to honor that promise. To me its a clear case and any lawyer in this country should be able to win such a case against GM.
All of you who really need the maximum capacity of the vehicle should form a group and talk to GM to get the 2004.5 exchanged to a 2005 for free (minus some usage).
This is only assuming the 2005 is indeed better in that aspect. You have to check carefully what figures they will give on the 2005s, maybe less possible trailer weight?
I just checked the specs again: the 2004.5 LLY 2500HD CC SB should be able to pull a trailer weight of 15.500 lbs. with Allison. Other cab configurations or body styles are more or less - this is all with fifth wheel.

Good luck!

I would not advise to reduce antifreeze to improve the cooling capacity, Glycerine has a 2.9 times HIGHER boling point than water, so to reduce the amount of it in the water will worsen the cooling capability for sure!

I just got off the phone with GM customer service and they are reporting no know problem. I am taking the truck to the dealer on Saturday to have them drive it. My take on the events will be:


Tech: Yup, it gets hot. That shore is a big trailor. Nothin wrong under the hood. Maybe you just need to back off and turn off the AC.


Me: Not acceptable.


Tech: Welp, lemme call GM.


GM: We will let you know if this becomes an issue. Your engine temperature is within its operating parameters.


Me: So I can leave the AC on and call you from the side of the road?


GM: We will document that you are having issues.


Me: FIX IT!


GM: ...............................





Do you know how long it took me to convince my wife to trade in the ford on this new truck?


I have full confidence that GM will make it right.

Like I said, try to collect more infos from other folks having the same problem. Establish measurements (thats a real big trailer you are pulling is NOT good enough). Its also to be understood that the A/C is running, the specs do not exclude this!
I there no way to write to GM in Detroit direct?
Since it looks like an inherent design problem the only way to solve it might be another vehicle to satisfy your needs.
Good luck!
Frank

Ok, so when do we start the petition to retrofit the new cooling systems or buybacks

I am taking the truck in on Saturday to the dealer with the trailer. On the way I am going to have the setup weighed. Hopefully they find something.

Just as I thought, the dealer has no solutions. My truck and trailer weighed in at 18,860 lbs. The dealer is supposed to be checking with GM tech support as to what is the expected temperature ranges for this setup. My problem now is since I always back off before I get to 225 they say that is normal. In order for me to show that there is insufficient cooling, I must let it get to hot. I do not want to do that. If there is someone out there that has had some help from the dealer, please let me know what they have done.





BTW the service manager and I were talking and when I asked if removing the CAT might help he said no and that would void the waranty. Any performance modifications would void the waranty.

To Exford


I too have a hot running duramax this is a known problem for the lly 04 motor as to this date there is 800 open complaints for this problem and to this date there is no known fix! I know this because i am in the middle of a buyback for this problem. Every single lly 04 duramax made has this same problem if you are in high ambient temps 95-100 deg F. or more and are pulling somthing bigger than a boat around 12000 lbs or more up a grade they all will overheat! My dealer has seen several of these cases. If you want to e-mail me rfinv@cox.net and i will give you my contact person at gm to deal with this problem!


I was going to purchase a 05 moddel but they cannot gaurantee the 05 models will perform better as the problem with the 04's popped up a little late in the year! They say that they have an electric fan on the 05 moddel but my GM contact person says thats to cure the problems they had with the A/C at some extended idleing situations!


Other than thats he believs they are pretty much the same truck! He even went so far as to advise me against the purchase of a 05 moddel!!!

I also had an over-heating issue recently. My trailer is about 8.5k empty, probably 10k loaded. While driving up the southbound “Grapevine” pass on the I-5, my DIC stated “Coolant Hot”. Of course I immediately shut off the a/c, and even turned on the heater to try to dissipate some of the heat. It was about 100 degrees outside at that time and as you can imagine that was no fun!

I have no engine or electronic modifications to my truck, even though I was planning to get the Banks System as soon as it is available. But I am not sure if it is wise to invest in this if this truck has an inherent design flaw. The only change I made to the truck is the wheels and tires, they are H2 wheels and tires, (315-70x17), but that should not change anything, right? I love the truck and do want a new one, but I am concerned as all of you are.

After thinking about this for a while I will post the name of this G.M. rep that i have been dealing with tomorrow I have to get it from work I will also post his phone # along with his extension maybe he will get the message from all of us! As I stated earlier it is all of the 04 lly trucks not just california but all of them!

Russmonster, I was in San Diego 2 weeks ago. When I was leaving out I 8, it began getting hot again. It was only 75 outside. I have an open issue with customer service at GM, but they say this is the first they have heard of it. Do you have a reference number?

Yes I do I was gona post the phone number for the gm rep i was dealing with but I forgot it at work if you need a conformation the complaints call Ken at poway chevrolet in poway california he has several complaints he is working on. otherwise i will post the number tomorrow night when i get home!

That would be great, I have an appointment at my dealer on Friday. Thanks!

I would be grateful to any help on this issue. My dealer can't do much except tell me that there will be no adverse effects as long as I stay under 250 F. Since I never let it get above that, I don't have a problem. I have always backed down before it gets close to that. Guess I will just keep pushing next time so that I get a code. Hope I don't end up on the side of the road.


I really think that this is a design issue that they are trying to ignore, but are fully aware of. I am not looking for a buy back or anything even close to that. I want some sort of fix.

Ok sorry for the delay... Here is the info for the gm rep i am dealing with.... Omar Armonte 1-866-952-4368 ext..58332


Hope this helps!

For those of you that want to help your truck out the RV industry has had this problem for years. There are several companies that make water misters that spray a little water out infront of the radiator when it's needed. It really works well and I'm sure would solve it for you , but, this is not a fix it only keeps the problem from ruining the truck while your on the road. If you check with RV stores like Camping World they sell these items. If I recall the kit are about $100. If you cannot find them and want one let me know and I can findout who makes them for you.

I had this happen just once. I deserved it though.


I was at high altitude and it was over 100 deg outside at 17k lb combined. Normally I go up hills in 5th, which is no problem. But I wanted to pass someone and it downshifted to 4th, and the temp started to climb. After a couple of miles the temp started to climbed and at about 230 deg, I got the Coolant Overtemp on the DIC. I slowed down to the speed limit, it shifted into 4th, and it went away. No more problems.


A tuner such as the TTS tow will keep the truck in 5th gear and the temps stay normal on my truck.


But any pickup truck I've ever used will overheat if you go WOT on extended hills when heavy. Your speed will control the temp.

It really amazes me as to the length poeple will go to these days to look beond a problem!


I am in the towing and recovery industry and i have several trucks that I haul 20,000 lbs. plus with on a daily basis! I have a 99 f-350 and a 02 f-350 both with 7.3's over 250,000 miles on them a 03 lb4 duramax 3500 and a 04 ford f-450 with the new 6.0l diesel. Fully loaded I can if I wanted to place a brick on the throttle point it at the hill on I-8 just outside of El centro Ca. at 100 deg.f they don't even think about getting hot! WOT or not if you pay 48, K plus for a truck it should never get hot at only 95 deg f outside!


Ford always seems to keep the same problems with all thier trucks Bad trany's as between the 3 that i have i replace them once a year! the lb4 duramax i have only had problems with Injectors at 230,000 miles I have on it now to this date i have gone through 6 sets of injectors and nothin else!


Now my new Flagship Duramax duelly with the lly motor. G.M. claims it will pull 20,000 lbs in addition to itself so were talkin about 27,000 lbs. it will overheat pullin my 9000 lb. boat up I-8 if i want to have my A/C on! If I turn my A/c off it will get hot but only to about 230 or so! Pullin 9K I only need about 3/4 throttle so this problem is not just at WOT. Now pullin my 15000 lb trailer it overheats in a matter of 2-3 miles from the start of the hill!


So now for you poeple that seem to think it is ok to pay 50K for a truck then add misters to it. You go do it.. cover up that problem! You poeple must be polaticians!

I am making 0 modifications until I get an answer from GM.

So now for you poeple that seem to think it is ok to pay 50K for a truck then add misters to it. You go do it.. cover up that problem! You poeple must be polaticians!





I agree for 50K it should not do it, but on the other hand I'm not going to let it ruin a vacation because GM cannot get there sh*t together. Let it overheat, break down, tow to shop = no vacation! http://www.dieselplace.com/forum/smileys/Ermm.gif They should fix it but until they do I want to enjoy the little time I get off work.

What I really want to know is if this is a design issue for anything over a certain weight, or is it something wrong with the programming or something on just a few trucks. Maybe we can look at VIN's and build dates of the ones that are doing it..

exford.....


There are 2 reasons for the overheating!


From what my dealer rep tells me is that it is mainly the egr system that causes it to run hotter!


The other reason is when Dodge came out with the 600 lb tq G.M. wasted no time matching it so they bumped up the lly motor and did not change the cooling system to compensate for the x-tra heat it generated. So now they are faced with the problem with where to put a larger radiator! (note the bigger front end on the 05 model) and as of today when i spoke to him they are still at a loss as to what to do!


I guess if you were in a hurry you could use misters as diesel tech suggested but I would rather melt it down on the side of the road! But thats just me ....Maybe then the would find a cure.

exford.....


There are 2 reasons for the overheating!


From what my dealer rep tells me is that it is mainly the egr system that causes it to run hotter!


The other reason is when Dodge came out with the 600 lb tq G.M. wasted no time matching it so they bumped up the lly motor and did not change the cooling system to compensate for the x-tra heat it generated. So now they are faced with the problem with where to put a larger radiator! (note the bigger front end on the 05 model) and as of today when i spoke to him they are still at a loss as to what to do!


I guess if you were in a hurry you could use misters as diesel tech suggested but I would rather melt it down on the side of the road! But thats just me ....Maybe then the would find a cure.





Looked pretty close today at an 05 side-by-side with 04 and while the hood is taller, the radiator, fan and clutch all appear to be the same and there has been talk here of electric fans on 05's and this one had none.


I have not had a overheat problem since the heaviest I tow is 9k lbs camper and boat even in 95F, but the fan noise is very anoying. I am interested it what is the final fix for this because I want to know I can tow more if needed.

Maybe I am being to picky, but I never had my engine temp gage even move on my Ford.


Ford temp gauges don't work http://www.dieselplace.com/forum/smileys/HiHi.gif





All of Fords gauges are switches. No movement. Either made or not made.








I can't agree more.

so would unhooking the EGR solve this? Or would it have no effect?





Would an intake+exhaust help lowe the temps or have no effect?


Would the Juice make it go up?Edited by: DuckhunterInTN

I am going to test the EGR disconnect mod to see if it helps my temps this weekend. Still have not had a call back from GM customer service.

so would unhooking the EGR solve this? Or would it have no effect?





Would an intake+exhaust help lowe the temps or have no effect?


Would the Juice make it go up?





I'm betting exford will report his problem solved by elliminating EGR. EGR add a lot of heat. It's supposed to shut off when coolant temp hits a certain level, but by then the entire radiator is full of hot water and the reserves are used up.


Intake is pretty darned good already on all D-maxes. A bigger exhaust could only help, but only a little. Either mod risks the warranty (well, even the egr mod risks the warranty, but it's difficult to prove . . .hmmmm, that connection must have fallen apart . . . .how strange).





Juice might locically be expected to make the temps go up, after all more fuel = more power = more fire = more heat . . . BUT, Juice also modifies injection timing which MIGHT actually reduce heat. Juice in level 0 (Timing only) might actually fix the problem.http://www.dieselplace.com/forum/smileys/Confused.gif

Yeah, I was kinda thinking the same things. I was thinking the Juice might actually fix it because the truck would run more efficiently...


So, (and this is slightly off topic) there is no big rush to install exhaust and intake after installing the Juice? What about EGT temps? Was the exhaust and intake recently improved or are they the same as on all year models?

I am new to the forum. I have a 04.5 3500 DRW CC Duramax, allison. I tow a 40' car hauler with living quarters. Weight unknown but just a guess about 16K. I towed to Ok City from Texas in May and did see about 230 on a climb. My previous truck was a 2001 2500 HD CC duramax & allison and I never saw more than 210 on the same run. I am making the same run this weekend and will see if more miles help. So far the 01 is far superior in that respect and fuel milage. If this overheating persists, GM will hear about it.

cant we just change to a lower temp thermostats?

Is it possible that they did something to the guage or built in a safety margin on the LLYs cause my Attitude monitor reads much less than my factory guage.? Maybe it reads off of different temp . sensor..? Edited by: FASTOYS

http://www.dieselplace.com/forum/uploads/947_dash.jpg

And they say this is normal!!!

Russmonster, have you tried disconnecting your egr? You will get a check engine light, but it would be worth it for the test. I can't get mine to run anywhere near that how with or without EGR so I can't test it for you. It's been too cool this year.

I read that earlier I disconected it for the trip today and no ck eng lite! But I got the overheat lite! I was only pullin about 7500-8000lbs and it took about 12 miles in 95 deg. weather! Up interstate 8 I pulled over after all the warning bells started dinging. Part of me wanted to continue and melt it down but I got the pic. I wanted so i pulled to the side and let it cool! This was only at about 3/4 throttle!


I was at the dealer on friday getting a data recorder installed and there was 6 other people there for the same thing all LLY's that run hot!


I don't normally get it that hot but I had that Data recorder and I wanted to make a point!

So it didn't make a difference.



Interesting. I wonder where the extra heat is coming from?

I just think that the air opening in the front of the truck is too small! I was lookin at the 05's on friday and i can find no difference in them except the air opening in the grill is about 50% larger! I even had the service manager look up the radiator part # and he says they are the same! so who knows ! The only thing I know is this truck is a total pile of crap! And to think I traded in a perfectly good 02 super duty for this!

Perhaps because the egr cooling tube is still connected to the exhaust it is still introducing extra heat into the system even though the exhaust gasses aren't flowing through it. I wonder if it would be possible to completely remove it altogether and plug up all the holes? I am sure it is possible, but it would likely be a lot of work to test it.

Who knows!!! The only thing I want to do is get my 48K back and a different truck wether it be a 05 model of another ford!

One of the EGR threads has a note stating that the EGR system is enabled when the engine temp is less than 212 degrees.

Russmonster's pic shows a temp of about 260 degrees. My guess is that this is why disconnecting the EGR wire did not make any difference in reducing the heat on Russmonster's truck. Even if the EGR wire was connected, the system would be disabled once the temp reached 212 degrees.

I am wondering why the Service Mgr told Russmonster that the EGR system was causing the problem, when the documentation says it is disabled when the engine starts to get hot.

****************************************
Exhaust gas recirculation (EGR) valve control will only be enabled during idle and cruising conditions while the following conditions are met:

The intake air temperature (IAT) is more than 5.25°C (41.5°F). EGR valve control will remain enabled until the IAT is less than 0°C (32°F) and will not enable again until the IAT is more than 5.25°C (41.5°F).

The engine coolant temperature (ECT) is between 60-96.75°C (140-206.15°F). EGR valve control will remain enabled until the ECT is less than 57°C (134.6°F) or more than 99.75°C (211.55°F) and will not enable again until the ECT is between 60-96.75°C (140-206.15°F).

The barometric pressure (BARO) is more than 74 kPa. EGR valve control will remain enabled until the BARO is less than 72 kPa and will not enable again until 74 kPa.
**************************

Somebody said it before, switching the EGR off at 212 F won't probably do the trick since the cooler is already very hot.
I thought there are not any other changes from LB7 to LLY only the EGR, the VTG turbo and some programming. And a different mounting of the injectors in the heads. So where is then the heat coming from - it don't think the turbo does it and also not the programming, otherwise how would all those aftermarked programmers work ...
maybe Russmonster disconnected the wrong plug since he didn't get a light on his California truck.

just my thoughts..

Frank

This news is particularly troubling. I went with the GMC D/A combo specifically to avoid having overheating problems. My truck only has 2k miles on it. I haven't tried towing my 9K boat up a grade yet.


I took a bath on my 2002 Avalanche, and bought this truck to avoid an overloading issue.


At this time, I left a message with Omar in hopes he will get back to me. I do intend to take a trial run up the Cajon Pass to see what happens. I sure don't want to overheat on my vacation.


This truck is so new at this point, that if a buyback will cure the problem, I'll make sure I do this on a hot day, with AC going, and pull up a good grade to make it throw a code.

Mahalkita,

.... or maybe a defective EGR valve that is stuck open even when the engine temp reaches 212 or the EGR plug is disconnected. That may explain why no code or no change. (Or maybe 20 other possibilities!)

Russ,


I noticed a couple of things from your picture. Trans temp < 200 and no tow haul mode? If I forget to put it in TH, my tranny will go above 200 on flatland. Also, rpm and speed indicate that you were not flooring it or may be the picture is after you backed off? Your dealer installed a data logger? Did they approve of the egr disconnect? I thought that the ecm could do the job of a data logger. I have had no luck with customer service, my dealer or another dealer. They all are telling me that 250 is "safe". BS I am with you, I had a perfectly good F350 that had never been to the dealer except for a leaky shock. The tranny temps were too high for me, so I traded for the D/A combo. This is a sweet truck if they can fix this one problem (oh yeah, through in some mirrors that are made for pulling trailers they claim it is rated to pull).


I am not towing hard again until labor day week. I am going to try the egr disconnect to see if this improves my temps, but I do not want to jeapordize my waranty.


You sound like you are getting close to at least putting GM in the position of doing something about it. What are they telling you, that you need to take it easy and back off when the temps are up there? Or are they admiting a problem? Customer service claims that I am the only one complaining.

I too traded in a perfectly good 02 f-350 that performed very well I traded it because the lease was up and i wanted the extra torque and the allison trans.


As for the things you noticed the tow/haul being off I had just crested the hill and was on flat level road and wanted it to shift to lower the RPM so it would cool off I had about 1 mile to go before i had a place to pull over so i could replace the coolant it blew all over the side of my truck and trailer.


As far as the Data recorder the truck sets no codes for the over heat as it is not a malfunction of the electronic system and the dealer that placed the recorder unpluged the egr for me they want to find a fix as well I have been workin with them for months on this now!


I am convinced it is a airflow problem myself.


As far as omar that guy promised me the world and come to findout he was just stallin me and fillin me full of false hopes tellin me he was gona do a buyback and swap it for a 05 model and then on friday he calls and tells me G.M. decided that this was not a concern for them at this time and it is normal for them to run HOT as he put it


I have contacted a buyback atty. that specialises in this stuff I will post his E-mail addy and phone number tomorrow (I forgot it at work) I am hoping that everyone gives him a call and open a claim it is no cost to you G.M. pays him direct. And he says he can do everything over the internet and fax machine!


The more people that opens a claim that G.M. cant control the faster they will find a cure of a fix!


If anyone wants to get more info you can e-mail me direct at RFinV@cox.net I also want to start a list of people that have issues with this problem to pettition G.M. for some kind of help!

Dumb question. I am sure you covered it earlier but do you have any type of screen front, billet grill or anything else that could restrict airflow?

One other thing I noticed while i was seeing just how hot it would get is that around 245-255 deg. it was really loosing oil preassure it had about 35 psi or so at WOT so this is another concern for me to let it run up to the 250 mark G.M says is normal! Normally it is around 60 at WOT maybe the oil cooler is lacking capability also! Edited by: Russmonster

No it is totally stock no aftermarket grill nothing

I think that there is too much crap infront blocking air flow. Trans cooler, Condenser, Intercooler. I think GM might fix it by moving the Trans cooler, making the intercooler fin gap larger, and make a vents in the hood or make more air flow underneath the truck pass the tranny.

Got back from my trip to Ok City Sunday evening. No major problems but the ambient temp going was 75 and 85 coming back. I did see the water temp raise to 215 from 205 going up on a 1.5 mile incline. I am quite sure on a long run it would have continued to climb as it did in May when it hit 230. One more major disapointment though. The 01 would average 10-11 MPG on the same run. This time, 8.0 MPG. That aint to good. I will participate in the petition. Just let me know

I have two long hills near my house and the ability to load up at will. I'm willing to "test" people's ideas for the heat issue.

Right now, I am very stock except for my huge 365/65-16 tires. I can get the engine hot almost at will. Could before the tire swap too, so no real difference there.

My theory is that the head redesign both changed the coolant flow in the head and greatly reduced the oil cooling that was splashing around under the valve covers on the LB7's
.

Do you think the high flow grill that is included with the snow plow package would help keep engine temp down. My lly has it and it has never got hot but I have only towed 8000 #.

If you can be at WOT, tranny locked, and not accelerating, the engine get hot. You just need a bigger, longer hillhttp://www.dieselplace.com/forum/smileys/Big Smile.gif

I was just wondering if this issue was limited only to Chevrolets or GMC's or both. I just wondered the different grilles would make a difference as far as cooling...

I'm new to this forum and the Duramax scene. Love the truck!! I picked up a 04.5 D/A CC SB in July. Made in April. Great forum! I've learned alot so far.


I was just wondering...isn't the radiator/cooling for the EGR still being exposed to exhaust temp/gasses even though the EGR is dissconnected? I mean,


the exhaust gas comes from the side of the turbo via 3/4 tube (or so) and then goes through the EGR radiator. This is where you cool the exhaust gasses before it goes into the EGR valve and then it makes its way into the intake. If I'm thinking correctly,the engine water is always exposed to the exhaust. So unplugging the EGR valve does nothing more than stop the flow of exhaust into the intake.The engine cooling water is still receiving BTU's from the exhaust . I would think you would have to close this exhaust path off to eliminate exposure to the engine cooling water to see any difference in running temps while towing.


Any thoughts? Mike

MDHD2500. You are correct. However I think you would still be better off without the Exhausy gasses flowing directly through it. But maybe its not enough. What you mentioned has crossed my mind. I just don't know how practical it is to alter it. Definately worth investigating. I think if I was having cooling problems I might look into this a little deaper.

You are correct, the cooling tube is on the exhaust/turbo side of the valve.

I should have a chance later this week to do an experiment. I will disconnect the EGR , make a couple of runs, then pinch off the coolant flow to the jacket and make a couple.

Suggestions?

Mike


I think you are on track with what is causing the extra heat load on the cooling system. Everyone seems to be posting high coolant temps after climbing a hill with a load on. Which would lead us to believe the Egts are heating the coolant up.


A few of the Class 8 Diesel Engines have had cooling problems because of the EGR Cooler. Some of the Engine Manufacturer are changing their coolant change schedule because of this extra heat load.Edited by: JakeGMCHD

I'm still new to the Duramax world but not to the fun of heat and LS1 racing motors where cold is king. It get's easy to forget that the natsy side effect of all of our power adder mods is more heat than the stock coolant system was ever meant to handle.


Do we have any programers for the Durmax yet that can control fan on and off temps or someway to manipulate the clutch setup? Are there lower temp aftermarket t-stats that can be used? These are things that could help with the heat creeping.


The ultimate fix though is to drop in a real radiator and a pair of electric puller fans to replace the stock fan. You'll move enough air with that to cool any load. A company like Griffin or BeCool could custom spec the radiator and there should be enough room in there for a pair of good sized puller fans from SPAL http://www.spalusa.com/html/dampframe.htm that you could run on a two stage electric switch in the cabin. It's a simple fix that we use in high horsepower LS1 apps all the time.


The alternative to a full replacement though would be to mount a thin line pusher fan in between the grill and radiator to provide a flow boost for the stock setup. This method could give you a boost of another 1600-2300 CFM of flow accross the radiator and since it's electric and on a switch you add it when you want it.


There may be some minor voltage issues taking these fans from 12v to 14v but it should not hurt their useful life too much. http://www.dieselplace.com/forum/smileys/Big Smile.gif


RickEdited by: MI Black Max

Did the LB7 have a coolant line to the turbo? I see that there is one on the LLY. Another heat source, but I'll keep that one hooked up!http://www.dieselplace.com/forum/smileys/Big Smile.gif

The LB7 has a cooland line hooked up to the turbo but as far as I know the LLY does not.

The LLY does, I just traced it out. Goes though a hard line from the water pump, under the turbo and manifold intakes and into the turbo on the lower passenger side.

Comes out on the drivers side about mid-upper turbo and switches to a rubber hose that T's into the return line through a valve of some sort. Looks like a check valve.

My LLY heats but it tends to be random so I'm seriously thinking of a thermostat change just to see what happens. Sometimes I'll just be cruising at 75mph and my alarm on the *** monitor goes off, Set at 215 degrees. My egt is disconnected and plugged so we have eliminated that factor. Other times I can be pulling hard and settles in at 198 degrees. My other mods did defiantly help with egt temps so this probably does effect engine temp also

There is 2 t-stats on the lly one upper and one lower. The dealer replaced those first and on mine it made no difference!


I have had about 300 e-mails from the posting I put out about starting a petition so I think this problem is allot bigger than I originally thought! My next step is to figure out how to start one!

I wonder if a major part of the LLY heat problem is the fact that its EGR system is based upon using high exhaust backpressure to force the exhaust into the pressurized intake stream rather than using low pressure exhaust fed to the intake side of the turbo; higher exhaust backpressure would certainly cause higher engine heat (and reduced MPG). Even with the EGR unplugged the control program would still call for the backpressure to be generated by the way the turbo vanes are controlled. I hope that the heat problem is sorted out in the near future as I plan to trade my so far flawless 2001 extended cab Dmax in on a crewcab.


Rodger

Don't plug or disconnect the coolant line to the turbo, its there to cool the turbo - otherwise it might be destroyed under high load!
Just my 2C

FrankEdited by: mahalkita

I wasn't going to plug the turbo line. I was just curious if the LB7 had the turbo cooled also. Looking for differences between the two engines.

After some offline conversations, I am fairly convinced that the water is boiling in the EGR cooler. The return line feeds back into the water pump suction line. When the jacket boils the steam goes straight to the pump causing cavitation in the pump which reduces flow which makes the temps get even higher.

This tracks with what I have seen. Once the temps start to climb, reducing power will not bring them down. You have to pull over or reduce the load to near nothing.

With this in mind, I have changed what I am going to do for a test. I don't want to pinch off the jacket outlet line, doing so will just backfeed steam into the pump through the hard piped jacket inlet. I will do runs with and without a blocker plate installed just before the EGR jacket. Someone did this in a seperate thread, but there was no mention of the overheating issue. They did mention the engine ran cooler.

Keep in mind from past experience the runs I have been doing on this hill will be either it overheats, or it doesn't. If I go up this hill slow enough, I can keep the engine temp down, but once it creeps past about 220, game over.

I'm off to fab my plate....

Fingers


This hill, how long and how steep? How much weight? Is that weighed or estimated?


This is an excellent theory. I read what the boiling pt was on the GM coolant but I don't remember what it is. Somewhere around 265 I believe. If our coolant temps are at 220, then part of the coolant near the turbo or exhaust has got to be much higher. Do you happen to have a infared thermometer? If you do, see what the temps are on the coolant lines to and from turbo and egr cooler once you get pulled over. With EGT above 1000, I would say that any liquid comming into contact with the turbo or the egr would vaporize. The question is wether or not it would liquify before the pump. The system is a closed system except for the one overflow tank. If any part is being turned to steam there should be overflow. I have not lost any coolant myself, but I have always backed off before 235. Are you losing coolant every time you get above 240 or so? What are your outside air temps during your test?


Why is GM not reacting?

The hill is 1-1/2 miles and starts about 5% and increases to about 15% grade for the last 1/2-3/4 mile. WOT overheats me around half way up the steep with a heavy load on a warm day. Coming down is a 20MPH reduced gear zone.

I can pass over the scales before my runs. They happen to be at the bottom of the hill at the supply yard.http://www.dieselplace.com/forum/smileys/Big Smile.gif The load I have in mind is about 26,000 combined.

IIRC the boiling point is 230-250 depending on the pressure cap that is on the system.

I am not loosing fluid, but the tank is almost full when I pull over and goes down as I cool down. I hadn't connected the dots about this before. Even minor amounts of steam injection into the pump intake will greatly reduce the pump's effectiveness. I suspect the steam recombines fairly fast, but not till it gets to the radiator. Till then, I would expect a less than effective steam/water froth in the engine.

Blocker plate is fabbed, ready for Thurday's runs.

I wish I had a pyrometer of some sort, but I don't. I would love to strap it to the EGR Jacket's outlet and watch the temps real time.

Blocker plate fabbed and installed. Took the truck for a run to get fuel for Thursday's testing. Hmmm, tranny temps are way down as are the engine temps. Engine is 195 without any loading, never over 210 and the tranny never gets over 185 and usually sits about 175. This compairs to rock solid 210 for the engine all of the time and 200 for the tranny. After warm up.

To me, that is a huge heat load difference!http://www.dieselplace.com/forum/smileys/Big Smile.gif

Checked "The Hill" with the GPS. Hill is 1-1/4 miles long. 4% grade for first 1/2 mile then increases to an average 10% for the rest of the hill. Some places steeper. Not as steep as I thought though. Total elevation gain is only 475 feet. Has been enough to trip the motor with a big load in the past.

How fast are you going on this hill, probably pretty slow. That would make things heat up faster. I see that you installed a blocker plate, is this on the egr exhaust flow or on the cooling flow to the egr?

just got the call from the dealer they could not find anything wrong with my truck 7mpg and over heated trans and motor thats bs but I will play along for now they said to bring my trailer back and they will have a tech ride with me up the cajon pass and see what happens

Blocker plate fabbed and installed. Took the truck for a run to get fuel for Thursday's testing. Hmmm, tranny temps are way down as are the engine temps. Engine is 195 without any loading, never over 210 and the tranny never gets over 185 and usually sits about 175. This compairs to rock solid 210 for the engine all of the time and 200 for the tranny. After warm up.

To me, that is a huge heat load difference!http://www.dieselplace.com/forum/smileys/Big Smile.gif

Checked "The Hill" with the GPS. Hill is 1-1/4 miles long. 4% grade for first 1/2 mile then increases to an average 10% for the rest of the hill. Some places steeper. Not as steep as I thought though. Total elevation gain is only 475 feet. Has been enough to trip the motor with a big load in the past.


Do you have any picture of this blocker plate? I am interseted to see what you came up with.

The ideal situation would be a valve. It would be nice to allow the coolant to flow in the winter to aid in warm up.

socal LLy,


I routinely tow a 7K pound travel trailer up the Cajon Pass and my mileage is in the 12-13 mpg range. Granted, I have an LB7 with CAT/EGR but the point being there is absolutely no problem temperature wise. When pulling the Cajon, the fan clutch usually locks on the last 1/3 of second climb (past Silverwood Offramp / truck scale). The fan clutch disengages just after cresting the pass. This is on a warm day.


Just providing a point of reference for another DMAX.

oc dmax the cajon is the only hill by my house my truck does not get to hot on the cajon but I cant drive all the way to the baker grade with the chevy tech the baker grade is when I first seen temps rise thanks for your reply and i will post the results as soon as I get them

Pic before plate install

http://www.dieselplace.com/forum/uploads/A17_mvc-560f.jpg

After install, left a tab so it would be easier to remove for testing.
http://www.dieselplace.com/forum/uploads/55B_mvc-561f.jpg

Nice work!

I run this in my truck and can tow anything anywhere, any temp. No problems.


http://stats.indextools.com/pa=100086136622&amp;js=no</NO> <A name=top></A>http://www.evanscooling.com/graphics/ecstext1.gif
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<DIV align=right>A Message To Heavy Duty Engine OEMs (http://www.evanscooling.com/html/trucks1.htm#)</DIV></TD></TR></T></TABLE>
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THE BENEFITS OF EVANS NPG COOLANT FOR DIESEL - HEAVY DUTY ENGINES



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<TD>TESTED 500,000 MILES WITHOUT COOLANT CHANGES OR SCA's</TD></TR>
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<TD>ENDS COOLANT MAINTENANCE AND EXPENSE</TD></TR>
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<TD>ELIMINATES CAVITATION OF CYLINDER LINERS OR PUMPS</TD></TR>
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<TD>ELIMINATES NEED FOR SUPPLEMENTARY COOLANT ADDITIVES </TD></TR>
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<TD>IMPROVES CONTROL OF METAL TEMPERATURES</TD></TR>
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<TD>ELIMINATES SYSTEM SCALING </TD></TR>
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<TD>IMPROVES FUEL ECONOMY</TD></TR>
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<TD><FONT face

How much did it run to change over?

I've got four gallons of Evans coolant I'll sell you. I used it in my high compression 327 gasser, using 91 octane gas, (highest available in California), and the car ran *much* hotter. Water cools the best. If you live in the southern belt, all you need is 15 to 25% antifreeze to prevent corrosion. Water dissipates heat much better than antifreeze.

Nice work and pictures Fingers! I like the idea of the tab on top. I plan on fabing a plate this weekend. Question, are there just two bolts that seperate the flanges? I looked at mine, and I thought there might be four.

When you eliminate trapped engine heat in the cooling system, you can modify an engine to run hotter, which increases your engine's efficiency. Optional minor cooling system modifications used in conjunction with NPG Coolant allow the operator to choose raising an engine's operating temperature and thus its power output and fuel efficiency. Usually an operating temperature increase of about 25°F produces significant fuel economy gains. Evans NPG Coolant carries off the increased heat smoothly and efficiently, eliminating destructive hot spots, cylinder liner and coolant pump cavitation, and uneven cooling problems throughout your entire cooling system.


http://www.evanscooling.com/graphics/npg_tfill1c.jpgThis isn't theory - it's in actual use by truck fleets and owner / operators who report gains of up to 1.5 miles per gallon fuel savings in engines modified to take advantage of Evans NPG Coolant's increased cooling efficiency. The cost of the changes necessary to take advantage of Evans NPG Coolant improved cooling properties can be recouped in a year through improved fuel economy alone. The elimination of down-time due to cooling system problems, and elimination of the cost of coolant changes are icing on the cake. These advantages, spread out over several units or an entire fleet, result in significant savings.





The engine may run warmer than 190, but you can do that with Evans.

Nice work and pictures Fingers! I like the idea of the tab on top. I plan on fabing a plate this weekend. Question, are there just two bolts that seperate the flanges? I looked at mine, and I thought there might be four.

Just two nuts. There are studs on the EGR cooler. You can spread the flanges enough to get a plate in, but not enough to get clear of the studs. So you have to slot the stud holes in the plate to slide around the studs.

On edit: Thanks for the support. I fabbed it in ~1/2 hour. Total install ~1 hr. Having a spare gasket to trace would have sped up the process.Edited by: Fingers

Fingers,


I haven't had a chance to look at my truck to understand, can you answer a couple of questions? Your plate is blocking exhaust flow, right? What difference is installing a plate vs. unplugging? Shouldn't you see the same cooling benifits just by unplugging? When the egr valve is shut, does it still let exhaust heat migrate to the egr exhanger?

The plate blocks off flow to the cooling jacket. When you disconnect the egr it just blocks flow to the engine. So when you disconnect the EGR stepper you still have exhaust gasses swirling around in the cooling chamber. The cooling chamber is cooled by engine coolant and circulated through the cooling system. Therefor you are greatly increasing coolant temperatures.


Disconnecting the EGR still accomplishes certain things such as faster turbo spool up etc. This takes it one step further and should aid in keeping the engine temperatures down when it is working hard.


One downfall to this mod is it will not heat up as fast. In winter this might be a real negative for some living in colder climates. Ideally, I think I will run a restriction plate in the summer and just unplug the EGR in winter.Edited by: Max Power

The plate blocks flow before it gets to the EGR cooling jacket. Initial results are encouraging. There seems to still be a lot of exhaust gas flow into the jacket even with the EGR valve, which is at the other end of the jacket, closed.

Max types faster than I do..http://www.dieselplace.com/forum/smileys/HiHi.gif

so does anybody have a verdict on this? I guess if I am not having the problem then I shouldnt worry about it.

Fingers,


Have you pulled the hill with the plate in yet?

One of the questions from the other post is will a block off still throw codes?

One of the questions from the other post is will a block off still throw codes?

yes

I pulled the hill a couple of times today, but it is cool here (~73F), overcast, and I don't think it proves anything. I didn't bother to do pulls without the plate. FWIW no overheat, not even a budge past the 220 mark. Again, not a good test IMO. I'll have to wait for a hotter day. Looks like it will take about 2-3 hours to do a complete test. With plate/EGR connected, without plate/EGR connected, and without plate/EGR disconnected. Aborted the testing once I realized it wasn't hot enough outside and that I had just made two runs without the AC on.

I was just wondering if this issue was limited only to Chevrolets or GMC's or both. I just wondered the different grilles would make a difference as far as cooling...


any GMC owners have this problem?

At highway speed 60 to 70 mph, empty, the temp gauge is about 200F, I've never had it past that, but never towed anything either. I thought that that seems a bit hot to me considering I'm unloaded


its a 2004 GMC.


I have not cat, no EGR, and I would have thought with that hole in the cowl induction hood that it might help cool things,


Rob

the blockoff plate will still make it throw the lite and codes

I wonder what the smallest size hole in the plate would be to satisfy the computer.

If we block off the coolant flow to the EGR, and we unplug the EGR valve, do we run any risk of something still heating up but not being cooled because of the coolant block plate and therefore causing potential problems later?


I am sure you guys have thought of it but I just needed to ask.

Falkirk,


The blockoff plate blocks the exhaust gas flow, not the coolant flow. With this blockoff plate, you can still leave the EGR valve plugged in, as youve blocked the exhaust gases before it hits the valve.


Net net: when you unplug the EGR valve, it should be in the closed position. Putting the block off plate in does the same thing before the EGR valve. Since the coolant jacket is close to the EGR valve, and your blocking off hot exhaust gases before the EGR valve, the theory is that the coolant jacket will not heat up more from the hot gases going to/thru the EGR valve.


From what I'm gathering at this point, you will still throw a MIL and codes, (if you have CA and Federal emissions) not because the EGR valve is disconnected....because now you dont have to disconnect it, but you will throw the codes because the MAF will not pick up a change in air flow that it should detect when the EGR valve cycles open.


I think Fingers is theorizing that you may be able to put a block off plate in there, and drill a hole thru it, and figure out how much air is needed to trick the MAF that the EGR valve is working. The theory is that you may not need FULL air flow to trick the MAF....Edited by: dojohnso

I may be wrong but I thought that the pictures of the blocker plate that Fingers posted earlier on this thread were blocking the coolent, and I thought his discussion before he built he blocker plate was about his theory that the higher engine temps were because the coolent was boiling in the coolent jacket. I am definitely no expert, that's why I was asking.


Just trying to understand.http://www.dieselplace.com/forum/smileys/Big Smile.gif

I may be wrong but I thought that the pictures of the blocker plate that Fingers posted earlier on this thread were blocking the coolent, and I thought his discussion before he built he blocker plate was about his theory that the higher engine temps were because the coolent was boiling in the coolent jacket.Â* I am definitely no expert, that's why I was asking.


Just trying to understand.http://www.dieselplace.com/forum/smileys/Big Smile.gif

The blocker plate is in the exhaust stream. The boiling in the jacket is what I think is happening, but blocking the coolant flow through the jacket did not turn out to be a practical exercise for many reasons.

Sounds great, I was not sure what I was looking at in the pictures.


So basically what your plate does is block any exhaust from entering the EGR system, which means the coolant in the jacket will circulate like normal but because of the lack of hot exhaust it will not heat up, resulting in lower engine temps.


I think I finally got it. Thanks

bingohttp://www.dieselplace.com/forum/smileys/Big Smile.gif

Props to you Dojohnso, with my new enlightend mind I went back and read your explanation, low and behold you were exactly right. I guess sometimes I have to hear things more than once for it to sink into my thick skull.


Thanks for the patience.

Falkirk,


No props to me...i cheated: I PMd Fingers! Im just a quick learner and can simplify (i hope) what is going on here. Kudos should go to Fingers....he's the bomb! Its his idea! GO FINGERS!!!! hehehe!.....and i want one of em cool block off plates when he's done engineering 'em!!!!!


Cut off the hot exhaust gases BEFORE they get to the EGR and water jacket....then you should be running cooler....makes a ton of sense!!!!!


D

Group effort guys. I only posted summaries of what had been discussed privately. I think it was MDHD2500 that started the idea of boiling in the jacket. From there, it snowballed.

Here is a pic of the blocker plate. Notice the scorch mark on it!

http://www.dieselplace.com/forum/uploads/9FF_mvc-568f.jpg

Nice picture, thanks. Should be pretty easy to duplicate, even with my hacker skills.


Dennis

I finally got results from G.M.today and found out that there is over 800 open claims about the 04 lly duramax's about overheating problems with them it happens only when towing up a incline or a grade at higher ambient temps around 95-100 deg f. and they are issueing me a buyback on mine since they have no fix for them yet and apperently they are at a loss as how to fix them. My only question is do the 05 models have the same problem? Or do i buy a ford of dodge?

After you get 10,000 miles and loosen the motor up some more it will not get that hot. My truck did that at first. Same hill, 10,000 miles later it did not get that hot.


You sound like my dealer!! I have 65,000 miles on mine and it still overheats going up a hill with a load. It does it even in 65 degree weather. It will turn on a Engine warm warning and if you keep going it switches to a Engine hot warning and sounds an alarm. My son is on his way to California , heavily loaded ,as I type and he has put 3 gallon of water it it.


It has been to the dealer more times than I can count. GM corporate knows they have a problem and they assure me they will fix mine when they know how. All this and I still bought another one. Isn't customer loyalty money great. Edited by: RickDLance

so would unhooking the EGR solve this? Or would it have no effect?





Would an intake+exhaust help lowe the temps or have no effect?


Would the Juice make it go up?





I tried this with limited results. It did however hurt my fuel mileage. The Juice did not help or hurt as far as I could tell.


I did however get 3 new injectors put in this week. They were out of the balance rate spec since new.


It did not help!http://www.dieselplace.com/forum/smileys/Cry.gif I have built the plates and will test next week on my way to Montana with doubles. Also in an attempt to stay somewhat legal, I removed the muffler today, not the cat. Still pretty melow sounding.Edited by: RickDLance

Another Forum member, Reliver, is making blocker plates of my design. They are 0.060" stainless steel and will cost $7.50 including shipping. You can either send your check directly to him at:

Bill Schmidt
5793 Westwood Drive
St. Charles Mo. 63304

or use my Paypal acount:

Daedalus1@verizon.net

Credit cards OK to the Paypal account. I'll pass the money and addressed on to Reliver. Make sure you include you Name and Address!


http://www.dieselplace.com/forum/uploads/DZ6_MVC-001S.JPG

Guess I will chime in to be on the list so I can see updates but I had the same problem. This was a long hill, hot ( 95+) and towing a 5th wheel in the 9200lb range. The fan would come on but I was watching my Trans temps sit at 200-210 and on occasion seeing the engine temp run up to 235. I then backed off and even shut off the A/C, really did not have a problem but I had to babysit it. Now that I see all the other problems caused by the same I am going to talk to my service adviser. Edited by: Wickedfn4u

I think the blocker plate will fix the overheating problem. I still want GM to address it. I blieve that they made the mistake of putting the valve on the wrong side of the heat exchanger. They admit that if it gets to hot the egr needs to shut off, but they didn't realize that the hot exhaust is still being exposed to the coolant. There is no flow of exhaust but there is still heat being transferred. Maybe GM's answer for a fix is to put another valve where the blocker plate is going.

Yea, probably reverse the current set up with the EGR valve on the exhaust gas side of the jacket.

The tube coming off of the exhaust pipe to the EGR heat exchanger is partially flex pipe. That is as far as I could feel or see. Has anyone seen how it is attached to the exhaust pipe?

I haven't read this one since it was only 3 pages. Back then people were mainly talking about the diff between lly and lbz being that they didn't upgrade the cooling capacity and also EGR. I talked to a local diesel tuner who is close to Edge in Ogden Utah about this issue(Baker Diesel). The owner swears that replacing the cat is the main heat issue on this truck. I have an MBRP 4" and an AFE Stage 2 and am having heat issues. He swears if I get the MBRP front pipe they will go away. What are your thoughts?

For you handy people, here is a pattern for the EGR blocker plate. Hash marks are one inch apart.

Enjoy

http://www.dieselplace.com/forum/uploads/2C7_Drawing4.gif

Fingers,


Thanks, saves me the trouble of making a template from a 3x5. You DA MAN!http://www.dieselplace.com/forum/smileys/Thumbs Up.gif


Dennis

My truck has a full 4 inch on it. I never really had the major overheating issues like some, but I never really towed with the cat in there so I couldnt tell you how much a difference it will make. It obviously wont hurt it any to remove it.

I haven't read this one since it was only 3 pages. Back then people were mainly talking about the diff between lly and lbz being that they didn't upgrade the cooling capacity and also EGR. I talked to a local diesel tuner who is close to Edge in Ogden Utah about this issue(Baker Diesel). The owner swears that replacing the cat is the main heat issue on this truck. I have an MBRP 4" and an AFE Stage 2 and am having heat issues. He swears if I get the MBRP front pipe they will go away. What are your thoughts?


He can swear all he wants it is not going to help much if at all. The egr blocker is going to be the ticket.

tws_andrew said,


The owner swears that replacing the cat is the main heat issue on this truck. I have an MBRP 4" and an AFE Stage 2 and am having heat issues. He swears if I get the MBRP front pipe they will go away. What are your thoughts?





I unplugged the EGR and noticed better fuel mileage, no real change in engine temps. Since I didn't get any lights I decided to remove the cat and put a MBRP front pipe on my already existing MBRP cat back system. Felt a difference in power and sound, but no real engine temp changes once it warms up, Then I made up a blocker plate and noticed that the exhaust note had changed slightly louder and at 1500rpm sounds pretty good, but really no big temp changes according to the stock gauge. It does seem to take longer to fully warm up, but once it hits about 195 to 200F it pretty much stays there, same as before. If I pass on the highway the temps will go up a bit more but not any higher than 200 to 210F. My stock temps were the same.


From these 3 mods I figure that I may have reduced the temp 5 to 10 deg, This is empty, at about 70 to 75 mph not towing average outside temp 75F


The real benefit I think is some fuel mileage and not having soot blown in my engine. I don't know what my EGTs are as I have no gauge yet. One other notable thing is that running about 55mph the engine is running cooler than before, but roll it up to 60 to 65 and the engine temps will go right back to 195 to 200F


Rob

I hate to tell you but I made a plate and drove 800 miles over the weekend and except for a slight increase in milage it made no difference! it took a little longer to get hot but it still gets hot!

Towing or empty. I would expect it to still sit about 200-210 but not to over heat when towing or under load.

Russmonster, it still overheated towing with the blocker plate? Did it help at all.

I was towing a horse trailer with one horse total weight was about 10,000 lbs. I was on I-10 from palm springs to phoenix there really is no big hills to speak of except cherico sumit witch is a small one but it climbed to 240 at 102 outside so that tells me the problem still exists althogh it did run a little coolor on flat level ground and had a little better milage! My next test is to remove the entire front grill assy then go again next week.

That will look good! Seems like we are all trying to solve GM's problem. Do you still have your CAT in? Don't they realize that alot of people come looking at these forums before they buy?


If anyone is reading this before they buy, don't buy a LLY if you need to tow heavy loads up big hills.

That will look good! Seems like we are all trying to solve GM's problem. Do you still have your CAT in? Don't they realize that alot of people come looking at these forums before they buy?


If anyone is reading this before they buy, don't buy a LLY if you need to tow heavy loads up big hills.

I have been on the phone with GM for 1 hour (50 minutes on hold) and all they can say is there are no reported problems and we will contact your dealership for you. I think next time it overheats, throw gas on it and let her burn!!!

Need to collect the case numbers from people and hit em with. Well what about case such adn such. That'll change a few things.

My Reference number provided by GM customer service is 1252353259. The CSR is Kurjural 1-866-952-4368.


So far only answer is that it is normal and within the range they see as acceptable. I am taking a trip tomarrow that will push it. I intend on getting pictures like russmonster and going back to the dealer. I have not let it overheat, so they say I have no real problem.

GM is full of BS. They are going to keep telling you guys this because they would lose millions if they admitted fault. Exford, if it were me I would not get it too hot either. If you http://www.dieselplace.com/forum/smileys/Nuke.gif the motor trying to show them that it is getting hot, they will likely say abuse and void your warranty. Or can they do that? It is my belief that they can. I was kicking myself after I bought my LB7 and not waiting for the LLY. Boy am I glad I got the LB7 now. No offense. I am just sorry you guys are going through the problems you are. http://www.dieselplace.com/forum/smileys/Disapprove.gifEdited by: dmaxfan

What the ????! http://www.dieselplace.com/forum/smileys/Confused.gif Before I purchased my LLY I read on several forums where guys were towing 20-30k lb loads with their 3500 D/A's with no mention of any overheating problems. I am not having overheating issues (knock on wood) towing heavy (16-18k lb toy hauler). http://dieselplace.com/forum/smileys/Question.gif Any other heavy haulers out there experiencing overheating problems?


We just pulled our 40' Sunnybrook toy hauler from Jacksonville, FL to Nashville, TN in 85-90 degree daytime driving. Weighed on the way out: 24,300lbs GCW. Tranny temp consistently ran 190, engine temp 200 except for 230 max on a couple of mountain climbs. We always run in tow/haul with overdrive disengaged when climbing any hills or mountains. Personally I drop back to around 60mph, however Mama JJ can't seem to get the lead out of her foot and keeps it up around 65-70mph!http://www.dieselplace.com/forum/smileys/Angry.gif I've experienced temp gains with every tow vehicle I've ever owned with extended climbs since the engine and tranny are working so much harder. http://www.dieselplace.com/forum/smileys/Geek.gif


I saw a post earlier where someone shifted back into overdrive after cresting a hill after a long climb in order to reduce operating temps. Don't be too quick to go back into overdrive after working your unit so hard. Even though you aren't climbing anymore you should keep the engines RPM's up a bit for maximum coolant and fluid recirculation which will cool the engine and tranny faster. Once cooled you can use the OD again.


There are so many variables associated with towing that might contribute to overheating, e.g. changing tire and wheel size, weight distribution, wind, frontal mass, truck/trailer tire pressures, etc., that I wouldn't attempt to state what may be causing some of these problems. All I know is my dually with stock tires yanks my 5ver up and hasn't looked back. 5700 miles so far, ain't even broke in yet. http://www.dieselplace.com/forum/smileys/HiHi.gif


I am running a uni-foam air filter, Transynd ATF and 75w140 synthetic in the rear axle. Other than that I am stock. Maybe the synthetics are helping to keep temps down. Hell maybe I'm just lucky so far.


I did disconnect the EGR so I don't know if that had anything to do with not overheating. I may reconnect it on the way back to see what happens.


Good luck with your trucks guys. JJ <IMG onMouseOver="this.style.cursor='hand'" o

Knock on wood again just to make sure. Hell I'll knock on wood for you if I thought it would help.


I pull a toy hauler loaded out at about 10k max. Now I know there is a temp difference from Phoenix to Florida but I have recorded temps from equipment hooked up by the dealer ranging from 246 to 253 degrees. Thats with outside temps from 70 to 110 degrees. I know ambient temp must have affect but mine will run hot even when 70 outside. I am totally stock except for K&amp;N and I have about 8500 miles on the LLY. If I leave Phoenix to go to the high country I know I will run very hot every time. It will do the same thing loaded as light as 6500 pounds. This is while trying to hold 50mph on 5% to 6% grades. It has tripped the "hot engine coolant" warning on the DIC many times. Normal temps for mine with no load run 200 or just a nick under for the tranny and 210 on the engine. I am following these threads very closely! There are alot of people who know alot more about this stuff than me and its good to see so many people trying to fix the problem GM gave us.


Love the truck, just hate this problem.


by the way my GM Customer Service ref # is 1-241757797

I think our Jacksonville Fl friend needs to keep coming farther west where the grades are steep, high and long. I have a stock 3500 SRW crew cab pulling a 36' 5th wheel (15000lbs). Threw Colorado the hot engine coolant light and the hot trans light has been on so many times I have lost count. Once this happens the computer begins to shut down your power. It is not fun when you are down to first gear with the Allison hoping to make it to the top... I was pulling this same trailer with a 2000 F-250 power stroke and "never" had a hint of problems. I thought with this Chevy the hardest part of driving was staying awake, was I wrong.... I am talking to GM regarding this problem. The truck only has 3800 miles on it. I want GM to fix the problem before I start trying to modify or rerout the egr or power chips.

I understand wanting GM to fix the problem prior to making any mods but if your experience is like mine, GM says there is no wide spread problem, no parts to be changed and the temps are normal. Basically GM told me the only thing left is arbitration.http://www.dieselplace.com/forum/smileys/Disapprove.gif


I made a very crude blocker plate just to see if it helps. I'm headed to Colorado Friday for a week pulling the toy hauler so I should get all the testing I can stand. I would have ordered a plate from Reliver but no time befor the trip. I have not experienced the power reduction from the computer yet. Now I'm really worried!!!


At this point I'll try about anything

Someone asked if the '05 had cooling system changes...


Let's swap pictures. I don't know what to look for, but I'll take measurements or snap a pic of whatever you'd like to see under the hood.


Ed

I have a question for you guys who know alot more about this stuff than me.


I have been concerned about the fact that the fan clutch is locked up about 90% plus when I tow. This is not just towing up grades this is any time I tow! (6k to 10k toy hauler) I asked a service tech at the dealer what the horsepower loss might be from the fan clutch running so much. he said it could be more than 20 hp loss when it runs.


my guess is because the engine runs hot the fan clutch is on pulling hp and lowering mileage drastically or because of the loss in hp I am running the engine harder to make up the difference thus using more fuel and creating even more heat.


Do you think the 20 hp loss when the fan clutch runs sounds right?


GM had the dealer change the fan clutch and both thermostats. No change in performance.

Just trying to give you guys some ideas. http://www.dieselplace.com/forum/smileys/Ouch.gif There are others on this forum that tow heavy with their LLY's and aren't experiencing the overheating problem. Fingers, don't you tow heavy with yours? Snoman? Others? What might we be doing differently that might help? For example, I've read on other forums that towing in OD can cause engine overheating and tranny slippage at very heavy weights. http://www.dieselplace.com/forum/smileys/Geek.gif


We have the best results when we collectively put our thoughts together. http://www.dieselplace.com/forum/smileys/Clap.gif The LLY has been out for 9-10 months and this is the first I've seen about an overheating problem like this. Good luck! JJ's out! http://www.dieselplace.com/forum/smileys/Big Smile.gif

Do you think the 20 hp loss when the fan clutch runs sounds right?





That's probably a bit high. Remember, the LLY is rated at 310hp and we're seeing probably a range of 240-255 hp at the wells for stock dyno pulls. That's pretty consistent with a 20% loss to the drivetrain which includes the pull from accessories like the fan, power stearing, alternator and waterpump and so on.


You'll find in performance cars, most people will put on an underdrive crank pulley and sometime altenator pulley to reduce the accessory drive speed by 10-25%. Those typically only give you 5-8hp back. So you figure worst case the whole accessory line on a car might be pulling around 32hp in that example while using an electric fan.


So I'd find it hard to believe that the fan is anywhere near 20HP to move what???? say 2600CFM of air??? Does anywone know what the airflow spec is for our fan???


Rick

On another note, how many of you guys that are ecounter high coolant temp problems have mounted your own temp gauge or OBDII scanner?.


I have found the stock coolant temp gauges to be typically very poor for GM. The Trans Am typically read 10F higher all the time when compared to what my scanning software and my own autometer gauge would report.


I have no problem believing that they are just as bad in these trucks. The real issue is knowing what the PCM is seeing because that's what your motor's performance is based on, not what the silly gauge is telling us.


Rick

I've been able to keep the temps in check, but I can go hot almost at will. Staying cool requires pulling a lower gear and going slower UP hill. On my "Test" hill third is required when I pull heavy 30,000 GVW. Frustrating, I have the HP to just fly up the hill too.

I dont need a guage to tell me its hot my truck spits all the coolant out so I figure the guage is rite! It may be 10 deg. off but it gets very hot! Just look at my doorhttp://www.dieselplace.com/forum/uploads/F9Z_image001.jpg1.jpg

I've been able to back off before puking. looks bad.

I agree the guage reading correct is in question. The only basis I have to get an accurate reading from is the fact that the dealer hooked up a recorder in my truck so I could record the temps I was telling them about. At 3 ticks from total redline is where I hit the recorder that got a 246 temp. Later a GM rep and the dealers service tech recorded temps from 251 to 253 the tech said it was about the same place on the guage ( 2 or 3 ticks from redline )


I put my rig on a scale and combined truck &amp; trailer GVW when these temps were recorded was 16400 lb.


I will try pulling hills in third and see if it changes but I am a long way from 30,000 GVW. I just hope the "Fingers Plate" helps out on my CO trip Friday. Well, its really not the "Fingers Plate". If you could only see how bad the one I made turned out.http://www.dieselplace.com/forum/smileys/Cry.gif It appears to work though. I made it prior to the pattern being posted.

I have 2 LLY's and I can make them overheat at will on I-80 with a EMPTY stock trailer. I am talking about setting off an audible alarm!! I have blocked the EGR valve exhaust tube with little results. I am going to remove the cat soon. My mileage is also 2 to 5 MPG LESS than my 01's or my 03. With a gross vehicle weight of 25,000 pounds I can blow out as much Dexcool as I want. As much as 1 and 1/2 gallons per hill. These trucks are stock and GM DOES know about this. They gave me customer loyalty money to try a second truck. It was not enough. Any body wanting to trade their low mileage 03 or 04 LB7 for my 04.5 LLY, PM me. One of my LLY's has also had 3 injectors changed!! Edited by: RickDLance

I dont need a guage to tell me its hot my truck spits all the coolant out so I figure the guage is rite! It may be 10 deg. off but it gets very hot! Just look at my door


You my friend are our official test mule. http://www.dieselplace.com/forum/smileys/Big Smile.gif


Check out Griffin's site and give them a call: http://www.griffinrad.com/


Ask them if they've got something in a 2 row x 1.25" radiator that can soak up heat for the Dmax and fit in with clearance on the Stock packaging under the hood. Figure those are good for about 20% additional cooling capacity between the additonal coolant, better air flow and better materials.


Actually, everyone who posted in this thread should call them over the next few days to give them an idea of what the market potential is. Who lives in SC??? Someone should drop their truck off for a mockup. http://www.dieselplace.com/forum/smileys/Big Smile.gif


Rick

So who's going to remove their CAT and see if their temp issues get better? Because other than some weird coolant cavitation issue, back pressure on the exhaust side would seem to be the cause to really heating things up.


Another, simpler method could be to tap into the exhaust prior to the CAT (1/8") and hook up a gauge to check the actual back-pressure. If a few folks did that then you could baseline low mileage/high mileage trucks. I'm sure GM has data on what a clean CAT's back pressure should be.


Wouldn't it be really silly if GM is using the wrong type/size of CAT in these trucks.


Just thinking out loud.





Denis

Dropped an Email to Griffen. Will let you know what they say.

Personaly I believe our problem is in the cooling system. These trucks are running good on the flat and down hill. Besides the radiator the water pump might not be able to circulate the coolant as well as it should. Or the thermistat is not opening wide enough when it's under a load.

Need to see what the return temps are out of the Radiator. The blocker plate, though not a complete cure, definetly reduces the heat load.

The removal of the CAT does allow for better air flow which means less heat being held in the engine comparment in general. All this really does is slow the heat build up for those that are overheating probably. The CAT is simply a part of the 100-150F EGT drop that you'll see advertised by the 4" exhaust vendors. That drop is good for the Turbo but there is still going to be high EGTs rolling up a hill under load for any period of time. So I don't think the CAT delete alone will see a significant enough reduction in heat buildup to really help the guys that are cooking.


I'm guessing that we use a standard T-Stat in the 180-185F range. Going back to my realm of familiarity in the LS-1 engines, we put in a 160F stat to start the flow sooner. This doesn't provide a significant benefit by itself though unless you can get the fans to come on sooner too. So we will typically set the start point of the first fan which is probably around 198F down 10-15F lower than stock. Then we do the same thing for the second fan to bring in the air flow sooner. Once we've out grown that mod then we move on to a better radiator and then perhaps better CFM electric fans.


The important thing to remeber when stiking in a lower T-Stat is that it will impact heater and therefore cabin warm up temps in the winter. http://www.dieselplace.com/forum/smileys/Big Smile.gif


Rick

I hate to say this but I believe the problem is not where you are all looking. Let's think about what's going on here. You have been looking at the EGR as the source of the problem. If this was true why then have we not had this problem on the LB7 version? The Water cooled EGR and CAT have been on every CA Duramax since 2002 and on the CA and Northeast Emissions vehicles since 2003 so there are 3 years of this prior to the introduction to the LLY version. Someone brought up the change in the grille area as a possible source but the grille changed in '04 LB7 as well. A simple test would be to remove the grille and run the hill test some of you are doing. It takes about 5 minutes tops to remove the grille, it's just held in place with clips. The increased power maybe the source but then again how many LB7's are running around with power adders and no overheat issues? There is something going on but I believe you need to start looking somewhere else to find the answer as the EGR just is not going to solve the problem.

My engine temp gauge on the dash reads about 10-20 degrees higher than my Attitude monitor. . . My Cat is already removed, but I haven't seen any difference in engine temps. I'm not a good test subject though, because I haven't towed anything since the cat was removed.


Russmonster,


That your wife or girlfriend taking pictures for you? Must be nice to have your own photographer. . . http://www.dieselplace.com/forum/smileys/Big Smile.gif


DennisEdited by: baimpala

[QUOTE=Diesel Tech]"the EGR just is not going to solve the problem".


What ideas are you thinking about as the main source of the problem? Is it a combination of a number of things? or one main problem.

Diesel Tech has a good point. I have always been amazed at how well my CAT/EGR equipped LB7 DMAX works pulling trailers to the Colorado River during the summer time in 105 to 110 deg Desert daytime heat. The truck cooling temps always runs at around 200 deg (or slightly less). If they climb much above 200 deg, the cooling fan engages and the temperatures slowly drift back to around 195 (I have watched this happen with the Edge Attitude monitor many times) So what is different with the LLY?


Are they using the same radiator?


The cylinder heads were redesigned.


There is a new turbo.


What else?????


The conditions you guys are seeing is totally different than what I (an LB7 owner) experiencing. There has to be a reason.Edited by: OC_DMAX

I am a firm believer that there are a few things going on at the same time. Today I'll focus on the EGR jacket. I have been able to do some testing today and, well you decide.

Weather: 80 F bright sunshine. 58 F dew point. Not that hot of a day, but I'll take it.

The Hill: 1-1/4 miles long. first 1/2 mile 8% grade next 3/4 averages 13% grade with the top even steeper. Four lane.

The load: Truck and Goosneck trailer GCVW 28,465 actual scale on first run with me in the truck. Used about 1/4 tank of fuel through the testing FWIW.

The Runs: 20 MPH rolling start at the bottom for each run. WOT all the way. AC on. I didn't time the runs, my fault. Fairly consistant 50 MPH when the hill starts getting steeper. First downshift at 3/4 mile mark (Allison) another when the hill steepens near the top 1/4. Again WOT. Topped the hill going about 20 MPH. Fan kicked in about the time the tranny down shifted on all runs. Just a coincidence? On these runs I didn't get any indication the engine had more power.

With blocker plate runs were identical:
195 at bottom of hill. rose smartly to 210 and held there till the downshifitng started, then rose to about 215, fan engaged, held there the rest of the hill.

Without blocker plate nearly identical runs.
First run:
210 F at the bottom of the hill. Never gets lower. Stays there till about 1/2 mile. Starts to climb. 215 F and fan at downshift. ~3/4 mile. Temps continue to climb. 235 F at top of hill.
Second Run:
Almost identical run but I had to break stride when a car got in front of me. I was just comming up on the real steep section. Entered the steep at a slower speed but I didn't get to look down and see what it was. The total run was longer time wise. I was at 235F within 100 yds of the top but never got higher. Still topped the hill at ~20 MPH.

It appears the blocker plate reduces the temp. In reality a 15 degree reduction is great!


I spoke with Griffin Thermal Products (info from prior post). They said they have not made a rad for our trucks yet but would expect a 20% to 30% increase in cooling if there is room for their 3" rad.


New rad along with some other mods may get the temps where they should be.


Fingers, I am kind of lost on some of the other stuff you are working on but very intrested in the results you get. Wish I understood more about the technical things you are trying to figure out. Intresting stuff.

It seems to me there was an improvement. If it never ran above 215. By removing the BTU's from the cooling system, it diffently helped the cooling system.It sure didn't hurt it. I am surprise it wasn't the complete cure. I will be testing this weekend to see for myself.


From what I have read the following are different on the LLY... Pistons,heads,injectors,turbo,Fan clutch (engages earlier),ECM (32 bit now) and something with the Ally. Not sure what that is right now. I can live with 215 degrees pulling 28,000 GCVW on that steep of grade.


Received my blocker plate yesterday. Installing it tomorrow!! Nice work and thanks!!


One thing I have noticed on my truck,when pulling a hill and it just starts to creep over the 200+ mark, the fan clutch engages and the temp continues to climb to about 210 and then all of a sudden the temp fell all the way down to 180 and went back up really fast to 200 and then stayed there. The first thing I thought of is what the heck is the thermosat doing?? Can somebody explain to me whats up with the duel thermostats... damn, I need to buy my service manuals. Is it still Helm that publishes them?





Mike

Never mind, I found the write up on the thermostat on the search. Interesting. It does explain why I seen temp fluctuations. I wonder...





Mike

Has anyone thought about where the injection timing might be at WOT? Maybe some have their timing a bit retarded causing the higher temps, as this doesn't seem to affect everyone.

Additionally at WOT if there are any issues regarding the fueling of the injectors or lack of it will also cause injection timing to change.

Will any of those code reader/programmers be able to read injection timing in realtime?

There's a lot of factors that can affect these engines, it would be great if one of the dealer's techs could hook-up their Tech-II unit and do a run as Finger's did.

Denis

I have been following this thread with some interest. Pardon me for my ignorance on this issue if I am mistaken, but ever since front wheel drive cars came out, GM has been using an electric fan to control temps. The thermostat opens at a temp between 180-190 degrees (F), then the electric fan comes on at 225 degrees (F)....


225?????http://www.dieselplace.com/forum/smileys/Confused.gif


Most of the posts here seem to be complaining of temps in the 200-235 range. They don't even TURN ON THE FAN in cars until 225! Why do you expect your behemoth truck to pull a heavy load in the desert, over mountains, and with the AC on at a temp below 200 degrees????


If your radiator is spewing coolant, then look for a pressure control problem,(or overfilled expansion tank) but IMHO the temp is not a problem. One additional note: GM says the clutch fan should engage between 85-96°C (185-205°F)


EdEdited by: Autoed

Can somebody explain to me whats up with the duel thermostats...


Mike





Taken directly from GM Service Information, hope it helps.


Ed


Thermostats (6.6L Diesel Engine)


The thermostats are coolant flow control components. The purpose of the thermostats are to regulate the correct operating temperature of the engine. The thermostats utilizes a temperature sensitive wax-pellet element. The element connects to a valve through a piston. When the element is heated, it expands and exerts pressure against a rubber piston. This pressure forces the valve to open. As the element is cooled, it contracts. This contraction allows a spring to push the valve closed.


The 6.6L diesel engine requires two thermostats for correct coolant flow. The front thermostat is a dual purpose thermostat. The front thermostat controls the coolant flow to the bypass port and to the water outlet. The rear thermostat only controls the coolant flow to the water outlet.


When the coolant temperature is below the rated thermostat opening temperature, the front thermostat valve remains closed to the water outlet and is opened to the bypass port. The bottom portion of the thermostat is raised off of the bypass port while at the same time the top portion closes the coolant flow to the water outlet. The rear thermostat also is closed to the water outlet during engine warm-up. This prevents circulation of the coolant to the radiator and allows the engine to warm up quickly. After the coolant temperature reaches 82°C (180°F) the front thermostat primary valve opening temperature, the front thermostat primary valve will start to open. The coolant is then allowed to circulate through the thermostat to the radiator where the engine heat is dissipated to the atmosphere. As the engine coolant reaches 85°C (185°F) and more coolant demand is required the front thermostat secondary valve begins to close the bypass port and the rear thermostat begins to open coolant flow to the water outlet. The thermostats will continue to control the coolant flow by opening and closing. The front thermostat will be fully open when the coolant temperature reaches 95°C (203°F) the rear thermostat will be fully open when the coolant temperature reaches 100°C (212°F). The thermostat also provides a restriction in the cooling system, even after the it has opened. This restriction creates a pressure difference which prevents cavitation at the water pump and forces coolant to circulate through the engine block.

Autoed


I expect my behemoth truck to pull heavy loads in the desert, over mountains with the A/C on at temps between 200 &amp; 215 because thats what I paid big $ for. If I wanted something else I would have saved some money and got an gas HD. I also expect it to do all this with reasonable fuel mileage. I guess the main reason I expect all this is because thats what diesel trucks have been know for historicly.


Thats just my opnion though. I do have alot of friends that feel the same way and they seem to have no problems getting their trucks to accomplish it.


High expectations? I guess some might think so.Edited by: mossaz

Hey mossaz, My thoughts exactly! We just took a trip through your area pulling our 5th wheel (15,000 Lbs.) The salesman at the Chevy dealership assured us that this truck would be the ultimate pulling machine compared to our F250 powerstroke. What a JOKE! I know you can relate! While sitting at the top of Wolf Creek Pass for over an hour, watching all the Fords and Ddodges whiz by us, next to the Continental Divide pull out, with our hood up, talking to ON STAR with every "over heated" light flashing at us, we were just wishing we were back in our old Ford! We barely made it to the top in 1st gear at 5 mph! The biggest hurdle right now is being able to talk to the right tech person or perhaps the person that designed this mess and get a fix or our money back. Let's keep working at it and see if someone can get through to somebody that can actually do something.

I have always been told that a gas engine can take higher water temps than a diesel. Is it true? If so that is the reason why auto'd


I am ready for a 2005 D/A test tow to see if they overheat. Will someone with one keep us informed.

Can somebody explain to me whats up with the duel thermostats...


Mike





Taken directly from GM Service Information, hope it helps.


Ed


Thermostats (6.6L Diesel Engine)


The thermostats are coolant flow control components. The purpose of the thermostats are to regulate the correct operating temperature of the engine. The thermostats utilizes a temperature sensitive wax-pellet element. The element connects to a valve through a piston. When the element is heated, it expands and exerts pressure against a rubber piston. This pressure forces the valve to open. As the element is cooled, it contracts. This contraction allows a spring to push the valve closed.


The 6.6L diesel engine requires two thermostats for correct coolant flow. The front thermostat is a dual purpose thermostat. The front thermostat controls the coolant flow to the bypass port and to the water outlet. The rear thermostat only controls the coolant flow to the water outlet.


When the coolant temperature is below the rated thermostat opening temperature, the front thermostat valve remains closed to the water outlet and is opened to the bypass port. The bottom portion of the thermostat is raised off of the bypass port while at the same time the top portion closes the coolant flow to the water outlet. The rear thermostat also is closed to the water outlet during engine warm-up. This prevents circulation of the coolant to the radiator and allows the engine to warm up quickly. After the coolant temperature reaches 82°C (180°F) the front thermostat primary valve opening temperature, the front thermostat primary valve will start to open. The coolant is then allowed to circulate through the thermostat to the radiator where the engine heat is dissipated to the atmosphere. As the engine coolant reaches 85°C (185°F) and more coolant demand is required the front thermostat secondary valve begins to close the bypass port and the rear thermostat begins to open coolant flow to the water outlet. The thermostats will continue to control the coolant flow by opening and closing. The front thermostat will be fully open when the coolant temperature reaches 95°C (203°F) the rear thermostat will be fully open when the coolant temperature reaches 100°C (212°F). The thermostat also provides a restriction in the cooling system, even after the it has opened. This restriction creates a pressure difference which prevents cavitation at the water pump and forces coolant to circulate through the engine block.

Whose the idiot that designed the cluster ***** they call a cooling system on these trucks. Are the LBYs outfitted the same way? Engineers, they sometimes just can't leave well enough alone!

So if anything screws up with the two thermostats then I guess it'll be a bear to trouble shoot.

Do Dodge & Ford have this complicated system?

Denis

I'm gonna throw in a curve here and hope somebody smarter than me picks up on it.


I think the high temp problem is a casting issue, with hot spots dealing with the redesign of the cylinder heads and/or possibly a poor recast of the block. A coreshift in the casting could explain why some trucks are worse than others. I have 2 LLY's and one overheats drastickly and so far the 2nd one overheats modestly, BUT BOTH DEFINATELY OVERHEAT !! I think the temp goes go up and down way to fast to simply be 2 small of a radiator. Throw in the new emissions and we don't stand a chance.

Several thing have changed from the LB7 to the LLY the EGR cooling and cat are the same. I believe the problem is coming from several sources and if they stack up wrong your in trouble. The new emissions requirements will cause the engine to be run at hotter temps. The EGR is turned off at any WOT runs regardless of temperature so I don't believe that's it. The cooling system looks to be the same thing but the motor is making more power at lower RPM and let's face it what it power? Nothing more than BTU's of heat, how much of it goes up in heat energy and how much of it goes to mechanical energy is the question. I don't have the answer that's for sure but I believe it's going to be a combination of things happening to make the problem. Myself, I install a mister kit and just hit the switch when needed until GM gets around to solving it but I don't tow heavy enough and often enough to let it bother me. A few hundred bucks and a small water tank and it's fixed for me. Just keep the water tank full when I leave for a trip in hot weather. I know we spent 35K and up but to let it stop vacation time for me just wasn't an option. I think each person needs to figure out what it's worth to them and proceed alone those lines. Anything you can do to reduce heat entering the cooling system will help, just as Fingers has shown but it didn't solve anything just reduced the starting temperatures. I believe if he had a longer hill he would end up back where he started. A bigger radiator will again get rid of the heat but it's still not the source of the problem, so that why I did what I did.

This really upsets me. I don't currently haul much more then 3-4g around- but was looking the future to getting something larger. I sure hope this is figured out soon. How do I complain to GM if it is not an issue now-but could be in a couple years for me? How is this going to affect the resale value if they don't create a fix? Living in <st1:State w:st="on"><st1:place w:st="on">AZ-(hot and long steep climbs is a way of life)</st1:place></st1:State> it's hard to ignore this issue. My truck pretty much runs at 210 all the time…so I am sure it will have problems with a heavy load. Sorry- I know this is a useless post to this thread- but thanks to all you out there that are really trying to find out a solution here. I check every day with hopes of the final solution

Several thing have changed from the LB7Â*to the LLY the EGR cooling and cat are the same. I believe the problem is coming from several sources and if they stack up wrong your in trouble. The new emissions requirements will cause the engine to be run at hotter temps. The EGR is turned off at any WOT runs regardless of temperature so I don't believe that's it. The cooling system looks to be the same thing but the motor is making more power at lower RPM and let's face it what it power? Nothing more than BTU's of heat, how much of it goes up in heat energy and how much of it goes to mechanical energy is the question. I don't have the answer that's for sure but I believe it's going to be a combination of things happening to make the problem. Myself, I install a mister kit and just hit the switch when needed until GM gets around to solving it but I don't tow heavy enough and often enough to let it bother me. A few hundred bucks and a small water tank and it's fixed for me. Just keep the water tank full when I leave for a trip in hot weather. I know we spent 35K and up but to let it stop vacation time for me just wasn't an option. I think each person needs to figure out what it's worth to them and proceed alone those lines. Anything you can do to reduce heat entering the cooling system will help, just as Fingers has shown but it didn't solve anything just reduced the starting temperatures. I believe if he had a longer hill he would end up back where he started. A bigger radiator will again get rid of the heat but it's still not the source of the problem, so that why I did what I did.

I agree there is more than one thing going on here. I am, as you might guess, a little disappointed the plate wasn't the "cure". It does seem to help, at least that is something. I will continue to look for sources.

An interesting thing about the new turbo is that part of it's function is to maintain exhaust backpressure to feed the EGR as commanded by the ECM. The LB7 EGR systems were not nearly as effective due to the lack of pressure to force exhaust gas into the intake. Just looking for candidates.

I hauled my wife's Spitfire out to Sacramento yesterday. Total towed weight was about 4500lbs. The temperature was in the low 90's when we left San Jose and was close to 100 once we crossed over to the central valley. Climbing the Sunol grade at 60mph (~3-4%, about 3 miles), the rearview mirror thermometer read 96 degrees. Engine temp stayed parked at one notch below the mid-point. Tranny temp stayed parked 1 notch below the 200 degree mark (where it had been after the first 10 miles).

The A/C on the truck practically brought frost to the windows. Even after being parked for 30 minutes in 99 degree heat, the cab was a comfy 70 degrees in about 5 minutes.

We'll see how it does with bigger loads and/or longer, steeper grades, but on our first run with serious heat there were no cooling issues under the hood or inside the cab.Edited by: driveawedge

Fingers yanks 28k lbs GCW up a steep grade at WOT without overheating, with big ass tires to boot! http://www.dieselplace.com/forum/smileys/HiHi.gif That's a very respectable pull for any 1 ton truck! Others are towing heavy as well without overheating. You have to wonder, if this were an inherent design issue wouldn't every LLY experience overheating when pulling heavy? http://www.dieselplace.com/forum/smileys/Geek.gif


Mama JJ and I just returned from a trip from Jacksonville, FL to Nashville, TN and back pulling our 40' fifth wheel toyhauler. GCW going up was 24,400lbs. She drove on the way up, I flew up to join her. Average speed 60-70mph, in overdrive except for long hills and mountain climbs. AC cranking the whole time and CD playing country tunes! http://www.dieselplace.com/forum/smileys/HiHi.gif She even forgot to disengage the 4x4 for a couple of hundred miles. No overheating issues the entire trip. Engine temp norm was 210, never above 230*, tranny 190, max 210*. I've found these are normal operating paramaters when towing, especially heavy. Outside temps ranged from 85-92*. http://www.dieselplace.com/forum/smileys/Geek.gif


Coming back we were about 800-1000lbs heavier since we filled the fresh water tank (100 gallons) and bought a generator due to hurricane Frances. I also reconnected the EGR for the return trip. Average speed 65-70mph, except for 4-5 mile stretch where I cranked it up to 75-80mph. The D/A pulled this load with ease. Before anyone jumps my sh_t for going that fast at that GCW no other vehicles were around me, straight shot with no turns. http://www.dieselplace.com/forum/smileys/Clap.gifSame temps coming back as going up. It seemed to me that the grade braking feature worked better with the EGR connected, could be mental though! http://www.dieselplace.com/forum/smileys/Confused.gif


MPG's weren't reliable due to the storm conditions.http://www.dieselplace.com/forum/smileys/Disapprove.gif I was very thankful that I had a dually though. That big ole bubble butt was planted firmly on the road going through 40-50 mph crosswinds. I saw quite a

I am not sure the ambient ouitside temperature was high enough to cause problems in your case. I also wonder if elevation could be part of the problem. These vehicles seem to overheat in the higher elevations. Keeping the torque converter locked will reduce temperature also. A locked converter does not have any slippage thus reducing heat. The cooling system has to reduce trans. heat as well as engine heat. The less work the heating system has to do the more heat it can pull out of the engine. It is my belief that the cooling systems on these LLY's have been built to close to the breaking point. Under normal conditions they are fine but as soon as they are stressed they don't have enough capacity. This is probably doe to the new emision standards.

DMacy, yeah the answer is out there somewhere. http://www.dieselplace.com/forum/smileys/Confused.gif I went back and read the previous posts to see if anything jumped out. Also went to the trailering/hotshot forum to see if any of those maniacs were experiencing overheats with the stuff they pull. http://www.dieselplace.com/forum/smileys/Geek.gif


Russmonster's issues are the most perplexing to me since he owns four diesel trucks and only the DMax is overheating. He did mention that he shifted into overdrive to reduce RPM's after a long, hard climb to reduce RPM's; ironically this could cause an engine to overheat. Also curious about the tire size on his DMax. Russmonster, intel please? http://www.dieselplace.com/forum/smileys/Big Smile.gif


cadent44, running 315-70x17 H2 tires and trying to tow a 10k lb trailer? Try getting on a bike and start peddling in 10th gear versus first; UUUUUUGGGGHHHH! http://www.dieselplace.com/forum/smileys/HiHi.gif Your 10k trailer is more like 30k to your truck with that large a tire since it can't get the power to the wheels like it should. You might try your stock tires if you still have them to see what happens? http://www.dieselplace.com/forum/smileys/Big Smile.gif Remember to keep the RPM's up above 2000 (2200-2500 ideally) when towing. Let us know.


dojohnso, I to traded an 02 Avalanche for my 04 Silverado 3500 dually 4x4 and am I ever happy. The AV was a toy, this is a truck dude! You won't even know that 9k lb boat is back there. Enjoy! http://www.dieselplace.com/forum/smileys/Big Smile.gif


AutoEd made some good points about overheating. 230 is not an overheat condition, heck I run in that range on every hill or mountain I climb when pulling the 5ver. I have towed my 5ver in 96-98* days and not overheated, though it did take a bit longer to get temps back to normal ranges after a climb. http://www.dieselplace.com/forum/smileys/Ermm.gif


As for the elevation causing the overheat that may warrant further consideration. <IMG onMouseOver="this.style.cursor='hand'" onMouseOut="this.style.cursor=''" alt='Click on image to open in new w

OK, couple of things for the record before we start pointing fingers at people instead of trucks.


GM says 250 is OK, I say it is not. Why, because pulling same hill with same trailer an 01 dmax temp gage never moves.


I can pull a lot of hills with out moving my gage, it takes the right hill to move it.


I will bet that any lly hooked to a load over 10K will overheat up the right hill.


The blocker plate helps the temps because it keeps hot exhaust from transfering heat from the coolant. WOT shut down of the EGR system does not do the job (same as unplugging). By the way, that is the first time I had heard that the EGR is shut off at WOT. I thought only the coolant temp shut it down.


Engineers tackle problems. The federal gov, tree huggers and unconcious poluters create the problems. I just followed some hippy in a sixty something VW micro bus up lizzard head pass out of Telluride that poluted more up that hill than I did on my 800 mile round trip. And he had 8 cars backed up behind him and would not pull off. &gt;sorry, off topic rant&lt;


If GM would just say that they are looking into it and will let us know when they find something, I would believe that they don't know what the problem is. Since they say there is no problem, thank you, call again, I know they know and it is going to cost them.

Bigger tires only reduce your starting torque. Once you are moving, it is a simple matter of HP, not gear ratios or tire diameters. I prove this every time I take my 26,000 - 30,000 GCW rig out on the road. Efficiency can be increased at speed by selecting gears and tires that keep the engine in it's sweet spot. The big down side of big tires is the rolling resistance that comes from a wider tire.

In other words, the tire size has nothing to do with overheating other than slightly higher rolling resistance, if any.

Though the factory prrogram tune increased power, I don't think that is the answer. People have been pumping up the LB7's without issue.

In my opinion, it is either the new head design, or the new turbo. Could be a bad combination of the two.

Still looking. Waiting on the Helms manuals to arrive so I can quote instead of guess what the changes are.

Exford states "OK, couple of things for the record before we start pointing fingers at people instead of trucks." http://www.dieselplace.com/forum/smileys/Confused.gif


Ouch! http://www.dieselplace.com/forum/smileys/Cry.gif If you were responding to my post then I totally hosed the context! I'll take that hit! http://www.dieselplace.com/forum/smileys/Big Smile.gif Personal attacks aren't my style! They are totally counter-productive to getting anywhere. Getting issues on the table and gathering intel (yes I'm anal) is where I'm comfortable. http://www.dieselplace.com/forum/smileys/HiHi.gif


In order to decipher the LLY overheat issue some are experiencing, but not all, it is necessary to put "everything on the table". Is it possible there is a design flaw in the coolant system of the LLY, yep!http://www.dieselplace.com/forum/smileys/Geek.gif Is it possible some are not towing properly, i.e. improper tire size/inflation; too low RPM's; too fast for conditions (it is very hard to stay at 70mpg on a 10% grade) without creating some additional heat; and so on, yep! http://www.dieselplace.com/forum/smileys/Hug.gif


My LLY pulls like a mule. At 25k GCW I could easily hold 80 mph on I24 through Tennessee's rolling hills in OD pulling a large 5ver toy hauler. But I'm very conscious of keeping the RPM's up sufficiently to keep all fluids moving constantly through their cooling systems, tire sizes, max tire pressures, and knowing when to get my foot out of the pedal and gear down for the conditions. Guys that tow heavy (Fingers/YamahaGrizzly/Geno) a little help here wouldn't hurt? http://www.dieselplace.com/forum/smileys/Embarrased.gif


We're now discussing ambient temperature and elevation as considerations as to why some of us can tow 25-30k lbs without overheating, but others can't tow 10k lbs without overheating. Same stock engine and tranny, the only variables being those that I asked about above. I'll yield to guys like Mackin, Diesel Power and others that know the technical stuff to answer. But only the guys with the overheat issues, not their trucks,&nbs

No big deal JJ, I think every one here just wants an answer. I know driving stile can affect temps, but not to this extreme. My driving style has kept me from overheating. I do back off at the right time. That time comes way too soon with this set up. The HP and torque race combined with emmision requirements out weighed designing a proper cooling system. Bottom line is there may not be anything wrong with the truck except a border line cooling system. Like I said, any lly will overheat on the right hill. I take part of that back, you will not overheat if you slow down and keep up your RPM's in time. That is not why I dropped 40K on this truck. I don't want to back off. I want the lack of power to be what slows me down. I can understand that. I know I can buy more power. The stock setup should be able to handle its own heat. STANDING ON IT! If you want to be OK with certain temps, fine. I see the other two passing me on the same hill after I have backed off, and not at the top with their hoods up. JJ, don't take this wrong, I am venting but not at you. At GM.

http://www.dieselplace.com/forum/smileys/Hug.gif JJ's OK! If I were on the overheating end of this post you betcha I'd be venting! http://www.dieselplace.com/forum/smileys/HiHi.gif


Gotta tell ya, nobody, and I mean nobody, passed me on I24 unless ole JJ let em! My rig easily weighed 6-8k more than others being pulled by "other brands" and I could leave them at will. Be gentle boys, JJ's just bragging! http://www.dieselplace.com/forum/smileys/HiHi.gif JJ's out!

JJ asked about my tire size well my boiler MAX. is totally 100% stock! heck i only bought it a few months ago! You stated nobody passes you and you pull 18 K up a hill are you on one lane roads or what! JK. I am almost posative it is a inherent design flaw and just a radiator size issue I have asked poeple to send me e-mails and addresses for a petition for GM and out of several different chat sites I have gotten almost a thousand poeple to respond all with overheating problems I dont believe with that many people it is just a driving style!


As far as shifting into O/D to cool it more I figure if you slow the rpm of the water pump the water will stay in the radiator longer to maybe cool a little more before circulating back to the motor! But who knows what is best.


I have turned my list of names over to my atty. I have retained to deal with GM over this problem and I will keep everybody posted about my progress with it!


If anyone wants to get a full refund on what you paid for the truck or wants GM to swap it out for a 05 model I strongly urge you to call this man.. John MCque @1-877-977-6779 I never even got a single bit of respect from GM until I retained him! Now they want to talk how funny that works! His fee's are paid by G.M. So I had nothing to loose!

my fan is on so much and the truck gets hot with any trailer I'm making the call

Russmonster, your frustration is understandable. I didn't mean to push any buttons, just looking for intel. http://www.dieselplace.com/forum/smileys/Big Smile.gif There are LLY's out there towing 25k and up and not overheating, yet others are towing much less and overheating? Now I'm no techie, but sumpin tain't right! http://www.dieselplace.com/forum/smileys/Ermm.gif


I knew when I posted that "nobody passed ole JJ" comment it might get a rise, but mostly from my Dodge and Ford buds. Remember I did ask for them to be gentle! http://www.dieselplace.com/forum/smileys/HiHi.gif


FWIW, I was on I24 just outside of Chattanooga, TN climbing Monteagle mountain, 6% grade (not too much) up to 2200ft elevation for about 4 miles. OK, its not a big mountain! http://www.dieselplace.com/forum/smileys/HiHi.gif I dropped my speed back to around 50-55 and got the RPM's up around 2800-3000 for the climb. Engine temp went to 230* and held, tranny to 210* and held the entire climb. When I finished the climb I kept my RPM's up and accelerated up to 60 with OD disengaged. Once temps returned to normal I took it back up to 65-70 and engaged OD with RPM's o/a 2200. There were other trucks towing 5ver's on that climb with me, none towing near as heavy, and I passed them all. Could they have kicked their trucks in the ass and kept up with me, maybe so? My point was more to the climb without overheating versus the other trucks not keeping up with me. Sssssshhhhhheeeeewwwwwww! Covering ones a$$ takes too much time! http://www.dieselplace.com/forum/smileys/HiHi.gif


As for the RPM low versus high for cooling efficiency question, maybe one of the techie types can offer intel. http://www.dieselplace.com/forum/smileys/Approve.gif


I was only trying to gain intel in areas that I hadn't seen discussed in earlier posts on this topic. Since I have an LLY I'm very interested in the outcome. Good luck with the attorney and GM.


JJ http://www.dieselplace.com/forum/smileys/Big Smile.gif

Point made. A truck with a LB7 would not have moved the temp gage. What was outside air temp and humidity? The higher the humidity, the better heat transfer you will get with the radiator. One of the big differences that RPM's make in temp has to do with EGT's. If you are pulling hard at low RPM's the EGT will get very high. High RPM's will cause fan to move more air across rad that has more water flow. If you want to keep it cool, keep up the RPM's. But there will be a point that will be too much. GM is betting that 99% of the users will never see this as a problem. Don't you think 230 is too high when a LB7 would never have moved the gage?

If anyone wants to get a full refund on what you paid for the truck or wants GM to swap it out for a 05 model I strongly urge you to call this man.. John MCque @1-877-977-6779 I never even got a single bit of respect from GM until I retained him! Now they want to talk how funny that works! His fee's are paid by G.M. So I had nothing to loose!





Let me addendum this comment. John MCque is out of CA and is only dealing with CA at this time. I spoke with him and he is a very nice guy and takes time to talk to you about it. Wow- pretty impressive for an attorney. I am going to locate my own out here in AZ at this time. Time for a ride up in the mountains this weekend with a video camera in hand. Then off to the dealer to play those games. I hope GM comes up with a solution- but I refuse to sit idle and wait. My understanding is some people have stated GM is telling the dealers not to document these complaints when you take it into service. Gee I wonder why.

If you have an overheat condition doesn't it register in the PCM? If so is there a way to ask for a printout of the codes at the stealership when you take it in for service. This may prove to be valuable documentation in any litigation. JJ http://www.dieselplace.com/forum/smileys/Big Smile.gif

Exford,


Temps were around 90*, humidity around 70%. Are you saying LB7 engine temps never budge when towing heavy into hills or mountains with less HP and torque than the LLY? That is unusual! I would have stuck with the LB7 in that case, plus turns out it has a better warranty. JJ http://www.dieselplace.com/forum/smileys/Big Smile.gif

JJ,


Yes, that is what started this whole issue for me. My buddy has an 01 with similar setup. We were pulling a hill and I called him on the radio asking how his temps were doing. His response was fine, why? Meaning same hill same day, he was below 200, I was at 235.


Hmmmmm.

Fingers,
the engine works harder (and might getter hotter) to turn big tires. Also the fan and waterpump turn slower for any given speed which will not help in cooling either.
So best for towing heavy is small tires or high numerical gearing in the pumpkins.

As mentioned before, the vehicle must perform like promised by GM which means with the max load any hill or mountain and any outside temp. (because GM did not explicit exclude those mountains or temps in their promise).
I have lived in Saudi Arabia for somethime before. Its MUCH hotter there than any place here in the U.S. and driving 4 wheelers in the sand dunes definitely heated engines up like hell - we did not shut off our A/Cs - of course not!
Bottom line - engine of my Landcruiser NEVER got too hot, its just a matter of design, means huge cooler, huge fan, extra fan in front of radiator etc. is technically possible, but GM DID NOT do their homework with the dmax. Its not acceptable, especially not for a 40+ K truck. And as exford put it - it will cost GM big money to fix it

just my 2C

Just my 2C

Fingers,
the engine works harder (and might getter hotter) to turn big tires. Also the fan and waterpump turn slower for any given speed which will not help in cooling either.
So best for towing heavy is small tires or high numerical gearing in the pumpkins.

As mentioned before, the vehicle must perform like promised by GM which means with the max load any hill or mountain and any outside temp. (because GM did not explicit exclude those mountains or temps in their promise).
I have lived in Saudi Arabia for somethime before. Its MUCH hotter there than any place here in the U.S. and driving 4 wheelers in the sand dunes definitely heated engines up like hell - we did not shut off our A/Cs - of course not!
Bottom line - engine of my Landcruiser NEVER got too hot, its just a matter of design, means huge cooler, huge fan, extra fan in front of radiator etc. is technically possible, but GM DID NOT do their homework with the dmax. Its not acceptable, especially not for a 40+ K truck. And as exford put it - it will cost GM big money to fix it

just my 2C

Just my 2C

This seems to be a common misconception. No, bigger tires do NOT increase the engine load because of the effective ratio. Everyone forgets that the tranny can downshift! Actually, I will pull a lower gear and spin the engine faster for a given load. Wider tires do have a greater rolling resistance. So they do add some extra load there, but not as much as people make it out. Larger diameter tires only hurt you in starting torque.

Went for a ride with the service manager from Bakersfield up the Grapevine to Lebec pulling my 36' 5th wheel. Truck temp crawled up to 250 with "engine coolant hot" light on at 45 mph. Transmission got to about 240 but this time the "transmission hot" light didn't come on. He said according to GM it is within the limits of the motor...? I told him that I can not drive a truck with all the warning lights flashing and have a good feeling. I think I will call Mr. MCque tomarrow.

Wow that SM had some brass balz to say that sitting that close to you. ( I will loan you a quarter to make the call)

why did he even waste your time and gas. I would of thrown him out the truck and let him walk back. what a joke.

Went for a ride with the service manager from Bakersfield up the Grapevine to Lebec pulling my 36' 5th wheel. Truck temp crawled up to 250 with "engine coolant hot" light on at 45 mph. Transmission got to about 240 but this time the "transmission hot" light didn't come on. He said according to GM it is within the limits of the motor...? I told him that I can not drive a truck with all the warning lights flashing and have a good feeling. I think I will call Mr. MCque tomarrow.


http://www.dieselplace.com/forum/smileys/Angry.gifThats exactly what they told me and I went back out to prove it would really over heat and I got pic's of the engine overheated light and a pic of all the coolant that boiled all over the side of the truck! and remember G.M. rates these trucks to pull 22k! Then I retained a lemon law atty. gave him the pic's ect...


The thing I have been thinkin about is G.M. also uses this motor in the 4500 and 5500 series trucks I have been talkin to a competitor of mine here in cali. he says he can tow 2 ford excursions one on the bed and one on the wheel lift at the same time those thing weigh in at 7800 lbs each and with the weight of the truck were talkin 25k easy and he has no problems with heat! I looked at his 5500 today and he has the vin 2 motor and i believe that is the lly they look identical to mine except for the massive radiator they used!Does anyone have any idea if they are the same motors if so how about diferences?

Fingers you are correct that IF the tranny shifts to a lower gear the engine and fan and waterpump will spin faster. But only IF that point is reached. Before that point occurs the load is higher on the engine, tranny etc. To spin the engine faster you could also downshift manually of course (to the same gear than the vehicle with the bigger tires...) You need also a true speed or some calibration to tell the control modules the correct rotation speed of those bigger tires for proper shifting. More stress on the tranny means also more heat on the cooling system which cools also the tranny. There are only 5 gears available and you have to run always one gear lower with the bigger tires to compensate for that.
Just my 2C

I guess the motors in the bigger trucks are indeed almost identical aside from different software. They are NOT producing as much POWER but similar torque at a lower rpm (Power = torque * rpm) and therefore not as much heat. And they have a bigger cooling system.

I guess the motors in the bigger trucks are indeed almost identical aside from different software. They are NOT producing as much POWER but similar torque at a lower rpm (Power = torque * rpm) and therefore not as much heat. And they have a bigger cooling system.


If this is true than that would even make me think more that the cooling system is just very insufficiant for the trucks we purchased! And has nothing to do with any flaws in the motor or design!


HMMMM More power smaller radiator what were they thinking????

It is common practice to underate big truck and heavy equipment engines to increase durability. Usually by reducing the top RPM the motor can turn but keeping the torque and low end specs strong. The cooling systems are always over spec. However, there have been problems even in big rigs with new motor combinantions. I've read they have had trouble with some of the new emmisions equiped rigs over heating.

Checked Chevy's website. The lowest rear axle ratio offered on the 4500 with a Duramax is a 4:30.1 versus the 3:73.1 in our light duty trucks. This may account for the 4500's ability to get the power to the wheels, plus keeps RPM's up throughout all gear ranges and avoid the overheat while pulling heavy.


So that begs the question, what if we changed to the 4:30.1? We would have much better acceleration, more towing capacity, and may eliminate the overheating problems? OK, I'm way out of my league on this stuff! Fingers, Max Power, put me in my place! http://www.dieselplace.com/forum/smileys/HiHi.gif JJ

Dangit, forgot to mention.http://www.dieselplace.com/forum/smileys/Disapprove.gif The designator for the 4500 Duramax is LRM, rated at 300 hp at 3000rpm and 529ft torque at 1800rpm's. So our trucks are putting out more HP, more torque at lower RPM's, and running with a lower gear ratio. Is this a recipe for overheating?


JJ http://www.dieselplace.com/forum/smileys/Big Smile.gif

JJ's on a roll, "Somebody stop me!" http://www.dieselplace.com/forum/smileys/HiHi.gif Don't Ford and Dodge offer higher rear end gear ratios in their diesel trucks? I would have preferred a 4:10.1 versus the 3:73.1 for towing.


This may open a door for those of us that tow with these trucks and wanted a higher gear(maybe it is lower, I get confused) in the rear end. The 4500 uses the same engine just detuned, the Allison is the same except our trucks have a parking pawl which the 4500 does not. I would love to get GM to change my rear axle to a 4:10.1 for free. Better fuel economy around town, much better acceleration, more towing capacity, +++++++!


Am I crazy? OK, dumb question since I already know the answer! http://www.dieselplace.com/forum/smileys/Wacko.gif


Russmonster, you have nothing to lose by getting them to do this with your truck since you are going after GM's ass to buy it back anyway! HHHMMMMM! JJ http://www.dieselplace.com/forum/smileys/Big Smile.gif

All single rear 3/4 and 1 ton Ford and GM only have 3.73 ratio with diesels. In Ford you can get 4.10 in the dual rear tire. This is my third diesel and all have had the 3.73. The other two (Fords) didn't have any heating problems. If you needed a lower gear you just down shifted..

OK, but wouldn't a 4:10.1 be sweet? Wouldn't it be a lot easier to keep the Duramax in its sweet spot for max HP and towing. I realize there is much more involved with switching the rear end ratio, but it would be at GM's expense. Or would this have absolutely no effect on the overheating problem? This kinda stuff is way over JJ's head.


JJ http://www.dieselplace.com/forum/smileys/Big Smile.gif

Yes it would allow us to run larger tires ,but our fuel mileage already suffers. Besides have you ever tried to run 85 mph and looked at the rpm's it's almost maxed with 373's 410's would really hinder us with stock tire sizes. I think most people that buy these trucks are looking for a vehicle to pull there travel trailers with and milage is a big factor. Besides I think 410's would interfear with the torque curve of the motor. At least with stock tire sizes! Just my opinion!

IMPROVED WATER PUMP


The Duramax 6600’s water pump has been redesigned to maximize coolant flow. The housing has not changed, and the pump is still internally gear driven to enhance durability and maximize packaging efficiency. Its impellor has been reshaped to move coolant more quickly through the engine.


NEW COOLING FAN RATIO


Fan speed has been increased approximately 9 percent by increasing the fan ratio to 1.37, relative to crank speed. The increase is accomplished by decreasing the size of the fan pulley, and it allows the fan to draw more air through the coolant radiator. Adjustments such as increased fan speed and the revised water pump are a component of GM Powertrain’s quest for continuous improvement – cost effective enhancements based on data from development and durability test vehicles that improve the Duramax 6600’s operation and durability.


http://media.gm.com/division/2005_prodinfo/powertrain/index.html


Looks as though GM has seen the concerns associated with the early LLY's by improving the 2005's. Now they need to satisfy you folks!

This gives us 2004.5 owners some good ammunition!!!!!

I'm a little suspicious that the 2005 upgrades on that link are really mostly for the initial LLY deployment in January 2004 versus the old LB7. http://www.dieselplace.com/forum/smileys/Ermm.gif They do mention an increase in torque for 2005, but other than that it reads almost verbatim from other press releases GM put out when the LLY hit the road touting the upgrades from the LB7. They keep referencing January 2004 as the date for many of these changes. How about some others check this out and advise. http://www.dieselplace.com/forum/smileys/Geek.gif


If they increase the fan speed by 9% it will drive those that already think they are noisy over the edge! http://www.dieselplace.com/forum/smileys/HiHi.gif JJ

JJ


For Release: Aug. 1, 2004


That is the date given for the information on that site. Perhaps GM had a few months of complaints to analyze and attempt to correct a bad situation this past year. Wouldn't it be nice to see GM "proactive" for a change?
<H1 align=center> </H1>Edited by: GMSUB20

Just spent about an hour reading this thread from the beginning. http://www.dieselplace.com/forum/smileys/Shocked.gif WOW. I've been away from the board for about 6 months so I was not aware of the overheating problems with the LLY.


One thing did catch my attention about the EGR cooling tube possibly boiling the coolant and causing steam to be introduced into the water pump where it causes cavatation.


Has anyone tried taking the coolant outlet hose of the EGR coolant tube and routing it thru a large auxilary transmission cooler temporarly mounted on the front of the truck, then back to the water pump. It seems that this would be a fairly easy way to condense any steam back to a liquid, and eliminate one of the variables that you are thinking about.


I've got an 02 LB7 that is 100% stock 49 state version and I easily see 1200F on my EGT gage when pulling fairly steep grades with only 10K behind me. I did this on the way from pheonix to flagstaff with 10K behind me. Set the cruise at 65, TH mode, AC on. Never got over 215 on temp, and 200 on trans, but my fan clutch did keep locked up the entire way to pull extra air over the system.


1200F siting in that EGR cooler tube puts quite a bit of heat into the cooling system.


Fingers, even with the EGR blockoff plate in place, that tube still might be getting hot enough to boil the coolant into steam on long hard pulls.


I wish you guys luck in getting this issue resolved with GM.


And for you folks that keep hearing from GM that there is not a problem........ remember that is the same company line they kept feeding us on the LB7 injectors right up to the day they released the letter about extending the injector warranty. They are not going to admit anything that would impact sales unless they are forced to. It's not just GM, it's any company.


Edited by: Searay90

JJ's still skeptical? http://www.dieselplace.com/forum/smileys/Ermm.gif I read that thread again to see if I mis-interpreted what was said. So only 8 months after initial induction of the LLY into service GM has: redesigned a new water pump; developed a new variable nozzle turbocharger; new cooled EGR; relocated the engine oil sensor; revised the fuel system with new injectors; new faster heating glow plugs(dang, can they can't get any faster?); etc. It also states the 2005 LLY's now come with CAT's, previously this was only on California models. This was true for the LB7's, however all 2004.5 LLY's have CAT's. Sumpin don't sound right Bubba? http://www.dieselplace.com/forum/smileys/HiHi.gif


Given that GM started the 2004 model year with the LB7 and ended with the LLY maybe they are just now marketing many of the LLY's changes. Granted there is a slight increase in torque over the initial LLY, other than that it appears little if any has really changed.


Easy way to find out though. Any DP members having access to GM's parts database should be able to pull the part #'s for the 2004.5 and 2005 LLY changes above to see if they are identical. If not changes have been made; if not, SHAME ON GM! http://www.dieselplace.com/forum/smileys/Evil Smile.gif


Why is JJ so skeptical? Does want a bunch of 2005 LLY's sitting on dealers lots because buyers are concerned about an overheating issue? Uh, no! The LLY's revisions were the saving grace for the LB7 injector problems. GM would much rather sale 100,000 of them and potentially end up buying back 1000 or so for those guys that tow heavy in hot conditions and overheat, and still have 99,000+- bought and paid for. Can it be true?


JJ http://www.dieselplace.com/forum/smileys/Big Smile.gif

All that info is just GM hype. It is just generic info about the LLY. All of the descriptions are for the 2004.5 LLY and probably aply to the 2005 LLY. The description of the injectors is exactly the same as the 2004.5. Some of the changes for the LLY are begininng to be problematic. The EGR, the cooling system and the injectors. I don't believe GM has found all these problems and come out with a fix on the 2005. Any change has to certified by Uncle Sam and that doesn't happen overnight. Remember the final design for the 2005 was done many months ago. Probably before the LLY was even released for production in the 2004.5. They already had these engines lined up and ready to go into the 2005s. They began to ramp up for production in the spring before overheating from the summer heat.

dmacy....he has a good point! I bought my LLY in april and reporterd my first problem 3 days later. But who really knows!

The Duramax 6600’s torque increase is the result of engine-control calibrations that take advantage of significant hardware changes introduced in January 2004. With these interim changes, the Duramax was identified by a new regular production option code – RPO LLY. The new RPO simply extends this V-8’s competitive advantage on every diesel offered in the heavy-duty pickup market. The Duramax 6600 is once again the unchallenged torque leader in pickups, without a corresponding loss of fuel economy.


Reading that press release from the beginning to see what they claim is new to 05 vs new to LLY. This clears it up. They just recalibrated the ECM for 05. Hardware changes were introduced in Jan 04. The part that really gets me is the last sentence. They even emphasize without.

OK now how about a flash to 05 programming for the 04.5 guys? That would be nice, probably just heat it up more though?

Need to gain intel from the guys that are running very hot or overheating. I posted the overheating issue on the "Ask The Tech's" forum, one possibility needs to be explored further.


BH in AZ states: JJ: I wonder if there is any correlation between the trucks that are running hot and those that are getting poor fuel mileage. RickDLance has posted some notes on his two LLY trucks stating that they are getting poor mileage and run hot. I got the impression that the mileage was worse on LLY #1 and as I recall, he said LLY # 1 also ran hotter than LLY #2.

If the truck is getting poor mileage and it is not smoking, meaning the fuel is being burnt, then I think the burning of the additional fuel would generate more heat.

I am also wondering if the new computer reflash may help somewhat since it does address fueling issues. http://www.dieselplace.com/forum/smileys/Geek.gif


I have noticed that my LLY does not smoke, even when I romp on it at night trying to get it to smoke. My fuel mileage towing is around 8mpg. The best mileage I have gotten was 19 at 70mph interstate driving when the truck was new (less than 1000 miles). Since then I don't believe my mpg's are as good, then again I can't keep my dang foot out of it either! wwwwweeeeeeeeeehhhhhhhhhhhhh! http://www.dieselplace.com/forum/smileys/HiHi.gif


BH poses a good question. Those experiencing the high temps or overheating, are your mpg's much lower than what you see other guys posting they are getting(18mpg+ highway)? AND when you romp on it do you see considerable smoke coming out?


GM has a reflash that is supposed to address fueling issues. Just maybe? Has anyone had the reflash done yet, OR any of you GM techs out there know what the reflash is doing? I certainly don't want to lose any power! JJ http://www.dieselplace.com/forum/smileys/Big Smile.gif

JJ I have gotten between 15-19 mpg unloaded and around 8-10 loaded and I have no smoke at all It runs great all the time! just gets hot at the first sign of real work!


I am still battling with GM but i AM SLOWLY MAKEING PROGRESS i FINALLY GOT THEM TO ADMIT THERE IS A COOLANT CAPACITY ISSUE BUT THEY HAVE NO FIX FOR IT YET!!!

My 1st LLY has gotten poor mileage and overheated from day 1. 6 mpg loaded at 18,000 pounds GVW on I-70 in Kansas and Colorado going west. Most of the time 7-8 loaded. MT at 75 mph lucky to see 14 mpg no matter what. Have had a couple of freak tanks better, but only a couple. No smoke. Overheats to the point of sounding an alarm, and has done it in 65 degree weather. Dealer changed ecm, thermostats, turbo actuater, and is reflashing tomorrow.


My second LLY started out good, but is getting worse. The last trip to Tucson I made I averaged 7.6 MPG loaded at about 20,000 pounds gross. Mt coming back it got about 15 mpg at 78 mph. No smoke.


On both trucks blocking the EGR seemed to help the overheating, but hurt fuel mileage. Recently had 4" exhaust put on second truck. Mileage up about 1/2-1 mpg, still getting too hot. Tried the Juice and mileage MT got worse, heavy loads were better, and lots of smoke. Called Edge today and they told me the LLY chassis dyno's at 20 HP less than LB7. Has GM lied to us again? My LB7's will get 2-5 MPG better and outpull the 04.5. I also was told by GM they know they have a problem and mine would get fixed when they knew what to do. Anybody what to trade????Edited by: RickDLance

Cannot make steam within the system without building pressure which will blow the cap. You will have steam then. Later! Frank

RickDLance, curious to see what the reflash accomplishes. I can't decipher from your post if one of the LLY's is still stock. Would be great to have a stock LLY reflashed.


The reflash is supposed to address fueling issues. I'm suspicious that GM may detune the LLY's to reduce hp/tq in order to reduce engine temps, conversely this might increase fuel mileage. In the race for diesel superiority hp/tq is what counts! Maybe they tried to squeeze the LLY too much for its existing cooling capacity? http://www.dieselplace.com/forum/smileys/Geek.gif


Please let us know the results. http://www.dieselplace.com/forum/smileys/Big Smile.gif JJ

A little late to this topic, one that interests me enough that I have been working on a solution while some of you are frustrated with the dealership (been there, done that http://www.dieselplace.com/forum/smileys/Angry.gif.) But first a question to those who have seen over 230F Engine temps and boilovers.


Was your fan running at the time you observed these temps? You will know it, it is very loud. Sorry if this was already discussed, I couldn't read all 10 pages.


Also, in the interest of getting to the bottom of it quicker, a pyrometer cost $50. If you'll measure your radiator temp with this temp gun when you see these conditions, we can work backwards. The water should be about 260 F if you are getting a boilover with a properly sealed cooling system. If it is lower than that, then there is a pressurization problem that will defeat heat exchange efficiency. I assume you guys have stock front ends and NO grill mods, flames, etc.

masterp2, JJ will bite!http://www.dieselplace.com/forum/smileys/HiHi.gif Did you have LLY overheating problems that you have fixed? If so wazzup? http://www.dieselplace.com/forum/smileys/Geek.gif


When my LLY temps get up to 230* the fan is fully engaged (roaring) and doesn't disengage until my temps return to normal around 205*. Does a pyrometer attach to the grille or radiator? Otherwise its kinda hard to drive to overheat conditions and dangle or stick something in front of the radiator while the LLY is burpinghttp://www.dieselplace.com/forum/smileys/Throw Up.gifon you. http://www.dieselplace.com/forum/smileys/HiHi.gif


We have the "too much fuel being combusted" and "engine coolant pressurization" scenarios on the table. RickDLance is having his LLY reflashed today at the stealership which is supposed to address "fuel delivery issues", hopefully he'll post those results asap. As for the pressurization approach, I posted a question on the "Ask the Tech's" forum regarding the impact of improperly installed thermostats(LLY's have 2 thermostats with different operating ranges). I asked what would happen if there were switched? Still awaiting a response from them.


masterp2, you know from my previous posts that I don't understand the pressurization scenario.http://www.dieselplace.com/forum/smileys/Wacko.gif Please explain in layman terms! http://www.dieselplace.com/forum/smileys/Big Smile.gif JJ

The pyrometer is a infra-red gun that tells you the temp of any surface you point it at. Point it at the hot and cold radiator area's to get an idea of actual water temp. Add about 5 degrees for the temp drop across the aluminum casing.


All common internal combustion motors are cooled with pressurized fluid. At 14.7 psi, atmospheric, water boils at 212. Additional pressure accomplishes a couple of things. The most important of these is that it permits your 50/50 solution to boil at a much higher temp, usually around 260 depending on coolant ratio and actual pressure. The higher the pressure the higher the BP (boiling point). You NEED that higher BP because when water flows through the radiator at a higher temp, the radiator is a more efficient heat exchanger, and is removing more heat. If say, the system is underpressurized (like an old radiator cap that loses it's spring), the boilover will occur sooner because the solutions BP is lower.


If you have a boilover problem or elevated temps, get a pressure check and look at your radiator water temps first. If those are normal, and this reflash does not effect a solution, then one solution is to add cooling capacity to the cooling system. I have developed an add-on that adds approx 30,000-40,000 BTU heat removal to the existing rig. I did this after noticing the problem that have developed with GM's smoke and mirrors approach to HP and Torque, not to mention EPA enhancement. It appears there is more heat with the LLY and nothing done to displace it.


Tell me also what your tranny temp is during this 230. I'd guess 200-230 also. AC effectiveness reduced?

Also IMO, if the thermostat's were switched, it could be a contributor, perhaps a major cause of lower than required system pressures. I don't really know enough about system to speculate further. If your truck goes down the line on a monday, who knows what can happen to it. If they look identical with similar fitment, I can see that happening. Where did that idea come from? Did someone here think it up?

First, that was one freaken outstanding explanation! http://www.dieselplace.com/forum/smileys/Clap.gif Even JJ could understand it, which for a guy that graduated behind Jethro Clampett is saying something! http://www.dieselplace.com/forum/smileys/HiHi.gif


My tranny temps normally run around 190 towing, when the engine temps climb to 230* the tranny runs about 205-210*. I am running transynd and deep pan, so maybe I'm getting a little bit more cooling efficiency. http://www.dieselplace.com/forum/smileys/Geek.gif


Is it not possible that both the scenarios we're looking at are in play here? If GM is putting too much fuel to the LLY's in order to win the HP/TQ war with F/D, they may have done so without consideration of the total cooling capacity of the LLY when towing heavy. My LLY runs 205* engine temps regardless of outside temperatures. It is only when I'm pulling heavy, on a considerable incline, that I see higher temps.


I'll float what may be a dumb question, my specialty I might add.http://www.dieselplace.com/forum/smileys/HiHi.gif The PCM's in these vehicles control everything but our bowel movements. It watches how we drive, samples the air, etc. Does it adjust the fuel/air ratio or somehow enhance the fuel ratio for the LLY when in tow/haul mode to improve towing power? Introducing additional fuel would increase engine temps, coupled with the heavy load it just might just be the wrong combination for the LLY? Be gentle please!http://www.dieselplace.com/forum/smileys/Hug.gif JJ