<!--StartFragment -->Seems my coolant and tranny get to warm. Warmer than other 2004.5 owners from what I have read. Out side air ranges from 65-90 degrees.

Towing 12-14K up any hill at 65+ the EGT can easily get to 1400 in OD (with Tow Haul ON). If I down shift (or if it does on its' own) the EGT's go down but the coolant climbs. I can get the coolant to 230ish pretty easy. I have been turning on the heat and opening windows to keep it at 210 on hills.

Same with the tranny. It can get to 210-230 pretty easy.

I am running a TTS Tow/Tune and it is lifted with 35's and stock gearing. Also a Volant intake.

From what I have read here switching to the no cat pipe won't help much.

Is there anything I can do besides slow down to 45mph or is this the nature of the beast?

Also off-road on a sandy trail at speeds of 15mph or less the tranny gets hot real fast, no air flow. Any thing I can do about this? Even if i install Mike L's cooler it won't help much in this case. Maybe rig up a fan?

I have also considered buying some of the Chevy SS front bumper 'air scoop' deals and rigging these up in my Buckstop bumper and running hose aimed at the radiator. Would this be a waste of time?

Also how much are the MRBP or other no cat pipes? Seems no one puts a price on the site or much info about it at all.

Nice looking truck!!!!!!!!!!!!!
I think I paid about $109.00 for the front cat less pipe.
As for the temp thing, you may have a bit of an air flow problem with that billet overlay grill and that fancy front end set up. I would try getting as much air as possible by removing the grill overlay. As for the temp getting hot, 230 is not really something to worry about as long as your fan is kicking on and cooling it back down a bit. If it won't cool down to about 210 or so with the fan on you may need to woory a bit, but I still think you have a air flow problem.
Damn nice looking rig!!!!!!!!!!!!!!!!!!
Dan

Thanks for the props :)

I also thought it was the grill. I removed it before this past weekends trip and got the same results.

The fan does kick on and if I don't turn the heat on it will not go back to 210 until I hit flat ground.

You're not the only reporting the problem. I'm fine, but others have seen problems.

I think having the A/C cooler blocking the intercooler and radiator wasn't the brightest move. I bet the radiator gets air that is at least 150deg.

It's odd ALL your fluids are hot.

What happens if you go uphill in 4th using OD lockout at 65?

Here's what I would do if I were you...

1) Do a test run with standard sized tires towing the same weight. Keep records, and try to get conditions to match.

2) If the temps are significantly lower, you're going to have to regear your truck. The 35" might put you in the wrong area of the RPM range. Or perhaps see what 4th gear does on grades. I find my EGT's towing uphill favor 2000-2500 RPM. This is why you might hear stories about me towing uphill at 75mph all the time. My engine likes it.

3) If none of that works, kill the kitty, and experiment with various tunes and RPM's.

When I first seen your post about you r new trailer I thought to my self I bet that rig will run hot when the weather warms up.My truck got real hot going thru utah last august and I took the grill off and it helped but there is a problem.my trucks trans gauge will read 215 just going to bigbear to snowboard.may19th I will be pulling my trailer to convict lake in the high sierra and that should surface the heating issue.

It's a comment from the peanut gallery, but I think McRat is right on the money.

We're talking a lifted D-Max running a very high overall gear ratio (35" tires with a 3.73 rearend) pulling 14K pounds at 65 mph?! That works out to be one hell of a load on that Jap oil burner!:D

I would be willing to bet a re-gear would drastically change the whole situation.

That Mike L. guy dreamed up some new tranny cooler as well that you might want to check out. If you get anywhere near Inglewood, though, keep a close eye on your oil and fuses.

First off, your truck is the shiznit. It looks great.

BUT, you can't seriuosly expect to get adequate airflow to the cooler stack in that configuration. If you look under a stock bumper there is a ton of duct work designed to direct airflow to the stack from the bumper. I haven't looked in to the aftermarket bumpers, but I would be amazed if the duct work was appropriately modified when the stocker is replaced. The lights on top of the bumper aren't helping airflow any either.

Take that in to account along with McRat's points about gearing as well as the fact that you are very close to gcwr and I'm not surprised you are overheating.

I wish I had a good solution for you, although my suggestion would be to lose the bumper and grille overlay. I'd be happy to take them off your hands :D .

Just my $.02.

Mike

I have a similar set up but I was getting hot with the stock tires.it made me re think getting the truck lifted I tried looking for the thread on over heating but came up empty.

I just towed my trailer from California up to the Yukon. I found the leaving the Edge on level 2 and with my foot in it I could see 1320 EGT's and the engine would start heating up. I believe the fan in these things comes on to late. I could here the fan come on however the temp had already climbed to 220. It should have a manual overide like big trucks.

I posted on this early in the month- my 05 pulling heavy but not at my max loaded weight (no quads) would run 230+ on any long grade. I too think the fan dose not come on soon enough and if the A/C is on its worse, temps were in the 45-65 range when we went from WI to FL the last part of march. I have the dealer looking into to the fan update for the snow plow prep pkg, came on at a lower temp if I understood correctly. I'll let you know.

When looking at your photos, your truck is really awesome, but that CST plate underneath the bumper looks like it would direct airflow down instead of up to the radiator.

Also off-road on a sandy trail at speeds of 15mph or less the tranny gets hot real fast, no air flow.

Converter is not locked. Its working hard in the sand. Probably not much you can do. Make sure you have Tow/Haul selected. That way if the tranny shifts to second, you have a chance of the torque converter locking up.


On edit: If your truck is a 4x4, not sure what happens with the torque converter locking commands when 4x4 LOW is selected. May want to give that a try along with selecting the Tow/Haul. You would be in 2nd or 3rd at 15mph, maybe to torque converter will lock. Worth a try.

You'll need to get up-to-speed on the LLY "Overheating" thread that started back in August 04 IIRC. It's a long thread with some good intel as to why the LLY's may be overheating. With the cooler temps of fall/winter that thread slowed to a crawl. Interesting to find some 05 LLY's with the same problems. :o:

See ya'll on the "overheating" thread. JJ :)

Was wondering as I read all of the threads if anyone had used one of the cooling agents added to the radiator fluid and if it had made any difference. I thing Lucas Oil and another company make an additive that is supposed to reduce coolant temperatures. I have thought about adding some but wanted to check and get results her first.

tabatasu,

This was discussed on the "overheating" thread as well.

Those with overheating concerns/issues might want to take the time to read the overheating thread to gain intel and get up-to-speed on what has been tried to date. JJ :)

I to have an overheating lly 2004.5. I personally think you can do anything you want as far as your front grille goes because it's not going to make any differance. These trucks are running right at there cooling capacity stock and any mods to improve performance or looks just make it worse! My truck is stock and I'm pulling about the same weight and have tried every RPM combo I can think of without success. The only thing I haven't done yet is to spray water on the radiator while pulling a grade. I'm not a happy camper and in my work I don't even try to pull my g-neck dump trailer.I am now paying half of my employees truck payment to pull that for me in the summer months. By the way it is a PSD and I wish I had one!!!! Not really but these Chevy's are great for driving around town but a work truck they are not

Wallbanger,

Not all LLY's are experiencing these problems. Has your truck actually overheated, by that I mean DIC showing "engine overheated" or have you burped your cooling system? :o:

Running higher engine temps, say 230*-250*, while hot, isn't considered overheating. I think the PCM shows overheat at 275* IIRC. :rolleyes: That being said when your truck starts seeing those kinds of temps on a long climb at WOT at higher elevations it may be in the pre-stages of overheating. :eek: Best to back er' down! :cool:

Many LLY's are towing heavy and ripping up/down the highways with no problems. You are not alone! Check out the "overheating" thread that is getting active again, lots of valuable intel there. Have you had your truck reflashed? Upgraded tires? :confused:

Later. JJ :)

mike330R--One way to address the heat issues in your allison is to have it pumped and the trans fluid replaced with amsoil atf or amsoil torque- drive syn trans fluid!! When you have it pumped-it means you get a complete service--completly cleared out--torque converter-cooler/lines-everything!! That should take around 40 degrees of heat out of your allison!! As far as the engine--amsoil has a new coolent that might be helpful to your duramax!! It's Propylene Glycol antifreeze and engine coolent!! It's essentially nontoxic and biodegradable!! Not a danger to anything!! Also, you could talk to greg Landuyt--he is a sponcer here--lubespecialist.com. He has evans coolent, i beleive it is waterless, which I"ve heard works well. Good luck.

Greg Carter Vermont

I have the same trailer, w/stock truck. For those who live in Southern California know where EL Cajon Pass is like windy and long. I tow 55 up that grade w/no problems, temp gauge does not budge. Truck has been reflashed. I am willing to bet that bumper or those tires have something to do with it. Check out the other truck, he has the same bumper you do. It also overheats. Makes me think twice about lifting my truck.

Not trying to "poo poo" any ideas, but most of these have been tried/tested, analyzed, etc. on the overheating thread. May save you guys some hard earned bucks to see what others have tried as well as help to understand what may be happening to make some of these engines run hot. :D

FWIW, the Ally is very susceptible to outside temps. Plenty of discussion on benefits of different tranny fluids on the Allison forum. Later. JJ :)

If that's a grill insert, you might consider pulling it off. I think most of the insert manufacturers warn that they might present an airflow restriction but leave it up to you to decide. I know they look good, but with the potential these trucks show to overheat, given the right conditions, you may wish to reconsider or go to the Big Mouth grill.
I just pulled mine off. If you look at the grill, that Chevy emblem is right dead center of the tranny cooler and that plastic chrome bar that it rides in can't be helping either.

Might want to consider temp controlled electric fans too. Something I'm considering for mine.

JJ true not all are having problems but not all are pulling near there load limits up long grades and yes I have replaced my coolant because of burping. Like I said I HAVE tried every RPM range to no avail I am not going WOT until it blows that would be quite stupid IMHO. I have read the Overheating thread I even contributed to it. I think it will be interesting to see how many 05's will have this problem. Personally I hope it's alot so maybe GM will start to take this problem seriously

the cajon pass is not very long try towing a load up the baker grade if you tow heavy 10,000+pounds in the heat watch that temp gaugeI have the same trailer, w/stock truck. For those who live in Southern California know where EL Cajon Pass is like windy and long. I tow 55 up that grade w/no problems, temp gauge does not budge. Truck has been reflashed. I am willing to bet that bumper or those tires have something to do with it. Check out the other truck, he has the same bumper you do. It also overheats. Makes me think twice about lifting my truck.

Socal. I agree the Baker grade is long & it does get hot out there. Before my Duramax, I had a 6.0 gas truck. It towed my trailer fine, the minute I put on a lift and tires (35x14.50) Super swamper thornbirds. My truck would overheat pulling grades. That is why I am in a Duramax now. So I am speaking from first hand experience.

Wow thanks for the replies. I'm not getting e-mail updates for some reason.

I think I may try and rig a ram air system up from the holes in the bumper aimed towars the radiator.

What gears whould you all suggest?

Mike330R, I have been thinking of lifting my truck since I drove it off the lot. I was going to run 9" lift on 37 inch tires. Was going to go w/4.56 gears. I would suggest you try 4.30.

Take your new tire circumference, divide by the stock tire circumference, and multiply by 3.73. I'd guess 4.30's. Don't know if those are avail for our axles. Might have to go 4.56, which probably wouldn't be a bad choice if you do a lot of heavy towing.

But before you spend the big coin, you can test it. Do one trip on OEM dia tires. If it does NOT help, don't waste your money on gears, unless you want to change gears for other reasons.

McRa,
I don't have my stock tires anymore. And it's look a lil weird with them on :)

I will try removing the skid plate though.

How would 4:30 or 4:56 gears affect take off speed and top speed?

This is off the subject but... Mike what kind kind of mud flaps do you have on your truck? I'm looking for a wide long flap like that to try and keep the rock chips down to a minimum. I'm running 325/60-18's with a small lift to keep things from rubbing.
By the way nice truck, I'll be watching the thread to see what happens with the running hot issues.

Thanks,
Bob

My 04.5 was bought back by GM, one of the many reasons was overheating. They put me in an 05 and I sure hope this one stays cool. My freind who has a 04.5 Chev built within 2 weeks of my old truck also has overheating issues. Now I know it is hard to believe anything you hear but.... He has a second proving session pulling his trailer with them (GM area service manager) in the next few weeks. They said they need a snap shot of the computer when the engine overheats. They did tell him they have a fix but they won't tell him anything about it and they have to make sure that he is not just saying things. He has been very persistant and everytime he pulls he trailer he calls to tell them the outcome. Maybe just maybe there really is something around the corner from GM.

Had the same problem with my 04.5. GM bought it back and now I have a 05. So far it has not overheated while pulling up hills. The heat is on the way so we will soon know. I heard if you take out the right headlight out of the 04.5 it will get the air it needs to keep cool.... What will they say next?????

Dura Flap!

Dennis rocks and is a great guy.

The new gears will put it back to how it was stock. You will get a better take off and most likely get your speedo to read much more correctly.
Dan

I had TTS program the tow tune to read correct on the speedo.

I will try removing the skid plate and maybe the cat remove 1st.

gtaylor states: "They said they need a snap shot of the computer when the engine overheats. They did tell him they have a fix but they won't tell him anything about it and they have to make sure that he is not just saying things."

So GM has a "SECRET FIX"! ):h Doesn't the PCM record an overheat condition? If so why do they need a snapshot? All they have to do is pull the codes. IIRC it may clear itself after so many recycles of the ignition though. :confused: If you are sitting on the side of the road overheated, when they flatbed your truck to the dealer they will see the DIC and be able to pull the code. ;)

So what do guys like JJ do that live in sunny, flat Florida with high humidity? I'm unable to get my LLY to overheat here in Florida, I'd have to head to the NC mountains on a dry/cool day and go WOT up the longest pass I could find to burp my truck. -:t That's not when anyone wants to learn they have an overheating truck! :o: SOL I guess! :o:

Oh well, my frustrations with the overheating conditions are starting to show! The service advisor at my dealership knew the exact words to put on the service sheet to get my truck reflashed. GREAT CUSTOMER SERVICE! If you have an option to go to another dealer you might try that first! ;)

Those of you that plan to hook your trucks up and tow to overheat be sure you remove any/all programmers, EGR plate/stick, put the CAT/OEM exhaust back on if you've removed it, etc. Any changes from stock will only open the door for GM to state you are out of original specs and delay reflash/repair. Even worse it may open the door for them to void your warranty! :mad: Don't put the bullet in the gun for them! :confused:

Old River, glad to see you got your issue resolved! :D JJ :)

Thanks JJ!!! It was living hell dealing with GM. They do not make it easy on a buy back. All I had to pay for was the extra options this truck has that the other truck didn't. I think it's time to take that truck and trailer on a trip to the west coast this summer....

McRa,
I don't have my stock tires anymore. And it's look a lil weird with them on :)

I will try removing the skid plate though.

How would 4:30 or 4:56 gears affect take off speed and top speed?

With the 4.30's you will top out at 115'ish. 4.56? Take 4.30/4.56 * 115. Acceleration should improve at freeway speeds and from a stoplight.

If nobody local has tires for loan, I have OEM 265's you can borrow. But if you want to change gears anyways, I guess you can skip that step.

i have read this entire thread and thought i would offer my personal experiences . i have 38.5 inch tires with a 11 inch lift . i tow a 28 ft trailer with a jeep inside about 11,000 pounds combined . towing the grade on the san diego 8 from glamis to san diego . had my truck floored the whole way up the mountain at about 75 mph . no overheating . engine temp stayed below 210 . and tranny temp stayed at normal operating range . i have also done this onethe cajon pass and the baker grade . luck of the draw ?

You know, I have been reading this and other threads about overheating issues which no one can seem to resolve and thought I would offer this input as to why some engines have a problem and others do not. And I am sorry to say, but I do believe that it is a very small amount who are actually experiencing a problem given the total number of engines/trucks out there.

Let me preface thsi statement by saying that I do not work for GM, in any way, and what I am going to say is my opinion only derived from 12 years experience as a ASE Certified Master mechanic. With that said, given everything I have read about what has been tried to resolve all your overheating issues, I am inclined to think that it could be a manufacturing defect in those engines. Let me explain.... I have found instances in all manufactured items that during the process the automated equipment can get out of calibration an, for example with a carburator incident that stands out in my mind, an air passage was underdrilled and did not operate. That carburator had been rebuilt 7 times before someone bothered to check to see if there was a blockage on the transfer passages of the carb. When they did they found the one which had not been drilled completely through. That carb would NEVER operate correctly due to this defect.

My point is that during the manufacturing process of the engines, it is possible (I repeat POSSIBLE) that a water passage opening was not made large enough, some casting excess was not removed,or broke off and lodged in a water passage, or some other defect happened which is not allowing the coolant to flow correctly or completely through the engine which would create an overheating issue which would never be found unless the engine was completely dissambeled and every passage checked. This of course is an unrealistic issue for a dealer to do and is exactly why there are Lemon laws which allow us to have vehicles which have uncorrectable problems like this replaced, or purchase price refunded if you so choose.

Now for you FORD Moles who may be reading this I caution you from taking this and saying that ALL GM products are defective, the carburator issue I decribed was a motorcraft carb (Ford). IT HAPPENS TO ALL MANUFACTURES in ALL industries.

Now for my disclaimer: This is a theroy bassed on what I have read here, and my general experiences, it is not to be considered to be the actuall cause of the overheating you are experiencing. It is only MY opinion and theroy. Again I am not an employee of GM or any of it's affiliates.

Whew

For what it's worth guys, I still think the D/A is the best out there and hope that you are not totally turned off of GM for your experience. Remember the old adage, the grass is always greener on the other side of the fence. Time and time again that has been proven to be a false statement. ALL manufactures have problems with thier products. NO Company is better than the other in dealing with these problems. You have to understand thier ultimate goal it to make a profit. This cannot be accomplished if they buy back every vheicle which has a loose bolt (an exaggeration). Of course they do whatever they can not to. AND THEY ALL DO THIS!!!

Ok, I am sorry I was so long winded here, but I thought I had to chime in.

John

This will not explain the variables in temps from truck to truck but it is another area to concider! The stacking in front of the radiator could be the problem. I believe that engine comartment is air bound! what I mean is the large frontal area of the grill opening is tryng to push or the fan is trying pull large amounts of air to cool the radiator,ac condenser and cooler but is having a problem due to the tight engine compartment restricting the airflow to the point of air not being able to flow fast enough to keep the temps low enough to prevent overheating. This was a problem in the early rv cutaway vans and gas powered rv's the temp's were high enough to cause overheating and alot of exhaust manifolds to crack. This could be corrected by venting the hot engine compartment but due to noise emissions may never be concidered.

This was just fuel for thought

The variable isn't the truck the variable(s) are the conditions. All you can do is back off to lower the boost level. Fresh external air instead of underhood is your best bet to help but the numbers are against you when you hold the boost high and eventually you will lose, and most often you will lose rapidly.


I will bet against ANY stock 04.5 or 05 dmax towing heavy up steep inclines at altitude (5000+ and higher is worse) on a hot (90+) day that tries to maintain speed.

Some mods will help you but the overall problem will remain.

You guys are coming up with ideas pretty quickly and it is impressive, but all of these have been hashed, rehashed, tested and disproven already in the over heating thread. Keep at it though, I would love to see a fresh new idea, but until physics change its the boost and nothing else will save you.

These trucks need an electric fan that has an overide, so you can turn it on before a big hill! That is what the big guys do. I know I drove in the mountians of British Columbia for many years in the hot weather.

Nice to see you back TX What would you think about a home built water misting system to spray the radiator and stack just to get you over that hill?? Do you think it would do any good or am I wasting 150.00?

Glad to be back and trying to help Wallbanger!

The fan is more than sufficient. It can cool the engine even with the entire grill area blocked by drawing air from the remaining cracks and crevices. This i already know from testing on my truck. That fan flows way more than any combination of electric fans that you could possibly mount there. I have run pusher and puller fans and combinations of both, they are great for saving power since the mechanical fan takes so much to turn but they just do not begin to move as much air. If you can stay above 30mph you can do without a fan at all since there is ample airflow by that speed. Besides there is just no place to put any fan in our setup, the only fan you could mount would be a pusher in front of the A/C condensor and would have no impact on the IC or the radiator at all, and there is a strong chance that after you are up to any reasonable speed the electric fan will actually impede airflow.

Water cools 23 times better than air, so yes a water spray is a great idea. Creates a hassle keeping it filled and keeping deposits from clogging the nozzles, but yeah that should get you over your hills just fine as long as you have enough water supply. It should take care of your overheat issue which is what you want until a true solution is reached.

Skip spraying the tranny cooler and the evaporator core and go straight for the IC, even though it will make your routing the lines much more difficult. If you are gonna take the time to install the system, then spend some extra time and make the most of the installation:ro) Mist in front of it from above and below and across the middle enough where you are pretty sure some of the water is making it past it to the radiator. This way you not only lower radiant heat to the radiator but you also lower outlet temps from the IC to the engine. That will give you a power increase which will also aid in defeating those nasty hills since you will have more power with less boost (the real culprit anyway). Even a slight amout of water making it past the IC onto the radiator will go a long way to cooling the water in the radiator.

So, spend the $150 and :grd:


You shouldn't HAVE to spend your own money and hassle with this, but if it makes your trip enjoyable then its a no-brainer and money well spent.

Thanks for your input TX Just looking for a way to keep MY cool till the General steps up and makes this right. Wife says no new truck this year and waiting for the new changes in 07 anyway. Hopefully this will not be an issue by then, or I may have to go with a cummins

Water injection systems hold promise as well. They lowers EGT's, increase hp/tq, lubricate the engine better... Commercial truckers have been using these systems for years with remarkable results. Several DP members have installed these systems, I'm anxious to see their results when towing heavy under the conditions that cause overheating. FredW, SD, others that have WI we need your input. ;)

As TxC stated, the overheating seems to be the culmination of IC heat from high boost, radiator temps, then tranny temps added across the stack overwhelming the engine cooling systems capacity. Dumping heat from the A/C seems hasten the process. :o:

Folks that have disconnected their EGR's and fingered/sticked their trucks and towed heavy at high elevations, what were your results? So far the jury is out as to whether this has any positive affect on temps, mpgs, etc. :confused:

Doesn't appear LLY's have overheating problems towing at lower elevations. If others are overheating under different conditions we need to hear from you!
JJ :)

I am not in the over heat catagory but it does get hot (230-240). I'd liek it to stay close to 210.

Someone mentioned the snowplow package upgrade? What is that? larger fan? Fan comes on at lower temps??

Mike330R, Have you tried towing without that bumper yet. I remember a previous post when you just got your toy hauler, you said the truck ran great. I beleive you did not have the bumper yet.

It got warm with the stock bumper (with grill insert) even with a small 14 enclosed trailer I had.

I had my foot in the gas granted, but it was a rather light load, 2500ish pounds.

I'm right there with you mike I got the same bumper and the same problems.My truck gets hot but that bumper is not the problem,I have taken off the bumper the grill and still gets hot.The bumper does make it easy to point fingers just ask my chevy stealer.anyways I have installed mbrp cool duals afe stage2 and banks six gun and bye bye kitty so I will see for my self what will happen.I will be leaving for the sierra on the 19th of may pulling my 26foot toy hauler it should get warm going up that grade from bishop to mammoth.

Something needs to be done.

I suggested adding some type of scoop to direct air towards the radiator.

Do any of you think something like the scoops on the SS front bumpers with a hose run from it aimed at the radiator would help?

How about drilling holes (or 1 big one) in the fender well inserts to allow more air out?

Also the hard rubber flap thing that is bolted to the frame just below the radiator. Maybe remove that?