Staff Edit: This is a continuation of this thread which has been closed due to the number of replies.

I spent a couple of hours pulling the brush guard and grille off the truck today to get to the stack. I used aluminum duct tape like the heating/ac boyz use and sealed the gaps around the stack. There are two large openings down low where the tie down hooks are located. I fabricated a couple of plugs for them out of cardboard then wrapped them in foil. I also used some of the foam insulation material normally used around doors, the kind with a sticky backing on it, and put a better seal across the inside of the hood and the stack crossmember. Plugged the holes behind the lights with foil to. KB, not sure plastic would work too well with how close it is to the IC. :o: Put everything back together, looks kind of ghetto, but the front end is pretty well sealed. :)

Almost forgot to mention. I relocated the outside temperature sensor away from the tranny cooler and attached it to the inside of the bumper instead. Appears to read more accurately. ;)

SOTP impression: tranny ran cooler, no significant difference in ECT's, though I really didn't expect much since the tstats control this. The ally normally goes up to around 180* when running 65-70mph in 90*+ temps. Temps ran about 140*, the only time I got it up to 160* was on a long hard acceleration from dead stop to around 70mph, then they started coming down. So it appears I am getting some benefit, but likely not enough. I need an air dam and the 5ver in tow to really put it through the paces! :cool:

I checked the right front fender, still very hot to the touch! The IAT is still feeding on very hot air IMHO. :exactly:

While under the truck I noticed that the ABS piece that holds the fog lights is already notched and has a couple of holes in it. Looks to me like it is for an air dam. :rolleyes: Do they make one for the other Silverado models? :confused:

Fingers, I take it making a run with the air dam isn't in the cards today? Too bad, would have been nice for TxC to show some positive results. Any other ideas guys? :o:

Personally my gut tells me it is a culmination of several different factors that results in high temps: too much boost creating exhaust backpressure and heat buildup in the block; coupled with lack of air flowing through the stack and removing BTU's; and finished off by ingestion of hot IAT's when the fan engages. As good as any other explanations I've read! :D JJ :)

There is no doubt the LLY makes more heat. And as I have said before, that is not the problem!! Getting rid of it is. That is where GM dropped the ball.

Seems that the investigation is going in the direction of more air through the stack. Probably a good path. But how do you reconcile ones that don't overheat with ones that do when the air flow should be the same? GMC vs. bowtie? Seems like very heavy and not very heavy both overheat so not convinced it is a weight factor.

Jim

The $64,000 question! We could end a lot of bickering with a good answer.

i was contemplating addressing this after I do a little more work, and getting some "fan-on" numbers. Since Fingers numbers gave me a lead-in to this, and since you ask, it would just be good to do it now.

As the numbers seem to show, the fan is about the only thing moving air at low speed, and perhaps even at high speed. The numbers suggest a inherrent stack P drop so miniscule as to relegate inherent airflow as non-existant. If the fan were not there, air crossing the stack would be about zero. And that's with the fan disengaged. We will soon see what the fan does for this picture, when engaged.

At high speeds, where we do the bulk of the overheating, the fan normally (in good designs) doesn't do much to help, most of the cooling would normally come from inherrent speed induced flow thru the stack. Obviously, as seen by the hill climb fingers ran with a dam, very small changes in flow create massive changes in cooling capability and IAT.

The fleet is all similar, but these flow discrepancies, small ones, between vehicles, can be the total explanation behind truck A that goes hot, and B that stays cool.

The engaged fan is additive to inherent flow. If on a scale of 0-5, inherrent flow is a 1, and fan is a 5, total is 6. If the next guy has 0 as flow, total with fan is a 5, or maybe a 4 if his clutch is a bit worn. So the guy like rick, who may actually have reverse flow, or recycle, during some conditions, is having to fight that with the fan, ie part of the fans energy is spent reversing an inherent issue.

Sometimes I'm not the greatest at explaining my thoughts, and these are not B&W issues, very conceptual feeling based on intuition, hope it was understandable, and as usual, disclaimed as my personal; opinion, not fact.

More simply, where a small change in configuration can a make a large change in cooling, then small things between trucks can be the difference. The truck just does not have any margin in these severe conditions.

So what's next? Thought we were very close to knocking the a$$ end out of this thing! :o: We established long ago that something in the LLY is creating more heat since the LB7 used the same stack without overheating. ;) We don't appear to be getting flow through the stack, that in and of itself is a prescription for overheating. While everything is on the table, can we stay on track and not digress into more possibilities until we have run this to ground? :o: IMHO the initial data looks favorable to this playing a major role in running hot. :exactly:

carhauler hasn't reported in with his mods and results. KB hasn't posted in a few so he's likely out there doing pressure measurements. I've done all I can think of, unless there is a way to get my hands on an air dam. I was actually thinking of buying one of those clear plastic bug shields like the older generations puts on their Mercury Marquis. You know the ones, they are clear and attach to an aluminum frame. Just might be sturdy enough to do the trick. Just haven't seen them anywhere for sale. I would still prefer something OEM if they are available. I'm searching the internet for options. ;)

Fingers, with your ghetto air dam in place am I correct the only thing you haven't done is seal up those holes right around the stack? That part took me about 20 minutes and half a role of aluminum foil and 15' of aluminum tape, hardest part was the big holes in the fog light ABS assembly. For your application that might not be necessary if the air dam drops down right behind them. I for one and very anxious to see what kind of pressure drops you get with things sealed tight and the air dam in place. Your initial tow results were very favorable. :D

JJ :)

My solution is no longer trying to "solve" the problem or overcome it, my solution is now motivate GM to make it right.

.

I agree!! As I mentioned earlier, GM will only react to media pressure, not good intentions. I really think it is great that collectively everyone has been searching for a solution, but it is GM's responsibility to resolve this! Unresolved it will affect resale values as this issue gets more widely known, not to mention the safety related issues this could have. Those of us that bought this vehicle based on the manufacture's representations should be upset. Even though my current vehicle does not show the same signs of the problems I experienced with my 04.5, I had to spend additional time and money to get these improvements and that is not fair! I did not buy a "light duty" truck to tow my RV, I bought a "Heavy Duty" D/A that was represented to be the "best" on the market. Don't get me wrong, I have been a loyal GM customer for many years, including 3 vehicles in the last year, but this situation is unacceptable and should be tolerated by anyone. I work in the automotive industry as a Sales Manager for a foreign Manufacturer, and I have first hand experience on how a “good” manufacturer responds to customer needs and issues. We all work hard for our money and we should at the very least get a product to perform as this manufacturer represented to all of us.

I think contacting all media outlets, local, regional, and national is a good start, however involving the Federal Government may also put additional pressure on GM. I am willing to do my part and if the rest of us can put as much time and effort as has been put into doing GM's job for them, we will get results!!

Lastly, anyone that knows of a legal firm that specializes in class action law suits would be helpful. Based on my experience, GM does react to an attorney’s call and letter. I will contact my attorney that represented me on my buy back to see if they can handle it or recommend a firm that can represent us.

I have been dealing with some shows and events and not been in the truck/Trailer( proabley good as its been 116 + here every day and I would have melted it by now) The service advisor told me the Rad is still in process and for some reason that is where they want to start,he felt sure its within a few days away ?? This is our busy season and I did ask them to push for before Pebble Beach ( Im out in the truck from about Aug 8 to 24 ) so its a good test run and he said he hoped to be able to get started.

TxC: I doubt the fan can create pressure into the box and past the filter. Much easier for the air to go out other places.

But it doesn't appear to be going other places. Even after sealing up the front end of my truck the right front fender is still very hot, the fan pushes the hot air from the stack right at the airbox. :o:

I question whether a pressure differential can overcome the fans directional flow towards the intake. Likely to require something solid or mod to the fan or shroud IMHO. ;)

TxC, hang in there dude! JJ :)

I think cadent45 is right I was forced to buy a different brand truck to do the work my business requires. I still own my 04.5 drw 3500 but it has been religated to pulling a 4000 lb cargo trailer. It is a shame cause the half ton GMC I traded for the LLY pulled this trailer without problem and much much cheaper to maintain and drive around town. Overall I'm out many dollars and after owning 17 GM vehicles in a row I am extremely disappointed on how I have been treated by GM. And yes I have been to several (4) seperate dealers and (2) district reps with this problem.

I question whether a pressure differential can overcome the fans directional flow towards the intake. Likely to require something solid or mod to the fan or shroud IMHO. ;)



That blast you refer to is a bit of a prop wash. That will remain, always. What will change with an improved pressure drop, is that air will be a lower temp, coming into the engine bay. make sense? The more air you can force over the rad, the less hot it will be, and closer to ambient. There is sooo much room for (fan off) heat exchanger efficiency improving here, , there is next to no flow at 70 mph.

Overall I'm out many dollars and after owning 17 GM vehicles in a row I am extremely disappointed on how I have been treated by GM. And yes I have been to several (4) seperate dealers and (2) district reps with this problem.

Look at what a few idiots pounding on a home keyboard have accomplished here, significant, yet with no resources compared to GM. They don't care. And nothing is going to change that.

Maybe I'm putting the cart before the horse, but if there is a patent attorney listening, and we have indeed split the atom, GM should pay for the solution.

I agree with what is going on here and am ready to bolt on any fix you guys can come up with. I would still rather drive my Chevy than its replacement (more creature comforts) but am still alittle po'ed at how I've been treated or ignored since july 2004 when I first brought this to GM's attention .

Fingers or anyone else that knows. Does your truck have this rubber type matting in the picture. I don't know how the airdam air will be able to get by this to get to the stack. Does it need to be removed?
Please HELP!!!!
Thanks
DAN
http://img349.imageshack.us/img349/6839/im00004719gj.jpg

Mine has it! While flimzy it appears to direct air coming in through the 2 slots in the bumper to the stack. It should be within the bumper, is yours? Without that piece the air may not penetrate the stack. I would leave it alone until the boyz run this to ground.

There are several openings around the piece that will allow air to divert away from the stack. I taped all those areas up today. Ally sure seems to like it, but still don't think enough air is penetrating the stack without dropping underhood pressures. JJ

Almost forgot, you need a MikeL cooler! lol JJ

Fingers or anyone else that knows. Does your truck have this rubber type matting in the picture. I don't know how the airdam air will be able to get by this to get to the stack. Does it need to be removed?
Please HELP!!!!
Thanks
DAN
http://img349.imageshack.us/img349/6839/im00004719gj.jpg

I didn't touch it. The dam is more about blocking air from under the truck than pushing it up to the stack.

[quote=dwrat;630611]Fingers or anyone else that knows. Does your truck have this rubber type matting in the picture. I don't know how the airdam air will be able to get by this to get to the stack. Does it need to be removed?
Please HELP!!!![quote]

That is GM's idea of an air director- I don't think we need to remove it. I just finihed enclosing the opening they left and plan on towing Monday to see if It helps any.

I did check and the 1/2 tons do indeed have a additional air dam of about 1.5" , I plan on checking futher tomorrow at the stealer- looks to be plug and play as it were. Hope it's enough to create that low p area that Fingers made with the gehtto dam. I also finish enclosing the air box- if I get good results I'll post a photo of what I did, right now it's very crude):h , but I think it should limit the amount of under hood air that can get in the intake.

I didn't touch it. The dam is more about blocking air from under the truck than pushing it up to the stack.

Fingers,
Thanks. now I know what your theory is and kinda understand. I though you were trying to direct air to the stack. Now it make more sence to me.

JJ,
Yes, my matting is within the bumper now. I just gooped it to the inside of the bumper. It was hanging down the other day. As for the mike cooler, is it hard to install and what about giving the stealer something to point at if there ever is a ally problem?

DAN

Look at what a few idiots pounding on a home keyboard have accomplished here, significant, yet with no resources compared to GM. They don't care. And nothing is going to change that.

Maybe I'm putting the cart before the horse, but if there is a patent attorney listening, and we have indeed split the atom, GM should pay for the solution.

Here is a linc to the law firm that has nailed GM on the gas motor tic that most all gm gassers have. There is also a freecase review there.
http://www.krohnandmoss.com/
http://www.yourlemonlawrights.com/contact.html#Get-Lawyer

Here is a linc to the law firm that has nailed GM on the gas motor tic that most all gm gassers have. There is also a freecase review there.
http://www.krohnandmoss.com/
http://www.yourlemonlawrights.com/contact.html#Get-Lawyer


I am using them on another issue I am not allowed to talk about, yet. Good results so far.

I am using them on another issue I am not allowed to talk about, yet. Good results so far.

Rick,

Do you want to contact them on this issue? If not I would be glad to call.

Rick,

Do you want to contact them on this issue? If not I would be glad to call.
I would rather somebody else do it. I don't want to confuse my other issue. I think before we contact them we need to sign up the people that want to participate. They need to have a failed attempt at repair for sure.

Christine Liddle is who is handling my other case.

I would rather somebody else do it. I don't want to confuse my other issue. I think before we contact them we need to sign up the people that want to participate. They need to have a failed attempt at repair for sure.

Christine Liddle is who is handling my other case.

I will contact try to contact Christine tomorrow, and I will start a new thread to bring this to everyone's attention.

?'s on this issue my 05 lly with no load what so ever runs at 210 and the fan is on all the time i have not towed anything yet for fear of it overheating but ithink i will try does this sound normal if i go up a 6% grade unloaded at 65-75 the truck will start to go higher than 210 so i am scared to even hook up my 5k lb trailer i am still using my 1999 5.3 1500 to do all my towing with, does this sound like the problem or should i just hook it up and start towing and see what happens

Yours sounds like it will be a hot runner. Please do hook up and tow. Lets us know what happens. Your numbers sound high for running empty, is it under 500 miles?

no its got about 4200 miles on it when it had 500 and under on it it ran at about 200 so i thought it was a little wiered that it got hotter with more miles

Was that the one about the redesigned pistons? I really can't buy that one. How do you explain some overheat and most don't? Me thinks there is a problem with that explianation. Unless you can link that with a casting problem.

What about skid plates? Any comparision on overheating engines and absence or presence of skid plates? 2wd vs 4wd? (Do 2wd have plates?)

Seems that the investigation is going in the direction of more air through the stack. Probably a good path. But how do you reconcile ones that don't overheat with ones that do when the air flow should be the same? GMC vs. bowtie? Seems like very heavy and not very heavy both overheat so not convinced it is a weight factor.

Jim

Jim,
I think I speak for everyone when I say that all LLY's will overheat given the same test. IMHO

ON:EDIT---This hasn't been proven because of the obvious!!! We all live in different areas ect. With the exception of RDL and carhauler we don't have identical tests nor 2 or more D-Maxs to compare side by side. I guess I'll answer that question when I hook up my friends trailer.

To all,

I'd bet the farm that if I hook up my buddys 30' weekend warior smooth side (14,500 loaded) and pull it up the grade near my house (7% for 12 miles) I could get my truck to overheat. Why would I do it? To give you someone on the left coast that can overheat bellow 4000Ft. We need confirmed overheaters to report problems the the dealerships, get our ducks lined up and start hammering the media conjunctively. If I can Tell my local media to contact your local media ect ect they might bite on the story and go all out.

I can't get my truck to overheat with my little 23' weekend warior (6300 LBS) but I'm definitely willing to put it to the test for our benefit.

TxC, JJ, KB, RDL, Cadent, Rat, Fingers, Carhauler, Huntsalot, Oilburnr, Nills, Me...pluss the countless others who have contributed. Take the proper steps to CYA and lets go

Think this through. To have a case, you need damages. If overheating led to an accident or something...damages. To have a story, a steaming GM in the breakdown lane isn't real compelling journalism, IMO.

Right now, you are all going to cook your trucks and shorten lifespans to prove a point?

Do what you want, Cadent45 can tell you exactly how to go about exercising your warranty rights, but that's all you have, a buyback. I don't see any damages, or a legal case. But don't take my word on this, I'm a nerd.

I think there's at least one other thread for this discussion though, this one seemed to be intent on self-help. Maybe I misunderstood. Plus we don't have near enough information to make a good presentation of cause/effect yet.

Don't get me wrong, I agree this is not our responsibility to digest. I'm just very picky about the ropes I try to piss up. Call me old. If this thread gets all caught up in a lynching, that's my exit cue. Maybe those that that feel strongly about this can organize, and of course, reference whatever comes out of the constructive end of this thread. That would also help keep people interested in solving this issue, there is a lot that can be done I feel. I lose all ambition when people start talking about attorneys and law suits, I hate all that stuff, makes me want to stay in bed. Just me.

So what do you think, take this to another Topic?? Cadent45 mentioned that.

Tlbob, get a signature going so we see what you got..You sound like a reverse flow/recycle flow candidate. Can you get your fan to shut off when you hi-rev the truck for 30 seconds?

Fingers, you may already be a step ahead of me on this.

When you do the tow trials, be sure to observe the oat increasing phenom, as Rick had. He (and others) have reported the oat increasing with increasing fan speed. With an eye on the possible cause being recycling engine air thru the stack. More than anything, maybe an air dam is preventing this ingestion, ie air running out the bottom, and around front to the stack inlet. My observation on reports is that this might be more prevalent at the highest speeds.

You boyz have been busy this morning. Just some food for thought. TxC is supposed to talk with the GM powertrain guy today. Suffice to say he has a lot of new intel to provide to them which may lead to a fix. We've documented that the stack isn't flowing, even at highway speeds. It appears we are on the threshhold of finding the fix, just wondering is this the right time to fire our guns? Supposedly GM is monitoring forums like this to see what's happening in the real world. If their eyes don't open wide when they see the masses getting ready to go "mental" on them then the gloves should come off.

Reality is once we start legal action and flood dealers with overheating complaints the value of our trucks is going to dive, big time! Nothing should make Ford and Dodge happier, GM has been taking quite a slice of their pie lately. I'll have to make my own personal decision shortly whether to trade my vehicle before values dive too far or to ride it out. Most class actions run several years to resolve through the courts. While in the end we may end up getting some, maybe all of our money back, as cadent45 found out there are legal angles for GM as well. Best to make sure we're not shooting ourselves in the foot, especially if it looks like we may have "found the fix".

TxC, recommend you have the GM boyz log onto the DP and view the overheating thread and polls as well as the class action suit thread so they are fully aware that folks are tired of GM's corporate response that "there is no problem". JJ

You guys need to make your signatures reflect GMC or CHEVY, the front end flow properties are different. So far I have not noticed the fan on oat increase on my GMC, but I'll be looking for it more now. At speed only, not sitting in the drivethrough

KB, it appears the LLY's turbo is creating backpressure through the IC which has resulted in several of the IC fittings blowing off. Is this phenom related to lack of stack efficiency? I'm not seeing it.

IMHO we have several things in play at once. The LLY runs high ECT's even unloaded. Doesn't take much to push it over the edge. If we have exhaust backpressure and a CAT restricting exhaust flow things will heat up, yes? If the stack is not flowing air and removing BTU's and the turbo literally stalled from backpressure wouldn't the hot exhaust gases proceed to cook the IC?

Additionally, the heat from the IC could be radiating heat through the A/C condensor into the tranny cooler. Note the ally spikes in temps quickly just like the ECT's do. The cooler appears to be rendered useless.

My money is on a 3 tier problem: exhaust backpressure cooking the engine; stalled air through the stack and excessive heat buildup; and the icing on the cake, the fan is either engaging either too little or too late, ECT's are too high when it finally engages, and it directs all that heat directly at the air intake! What do you get when you add fuel to the fire, MORE FIRE = MORE HEAT! This dousing of heat robs an already inefficient LLY of the additional HP we're asking of it by pressing the pedal even further to try to keep speed. We're feeding it fuel, it needs cooler air! This might explain why they tend to overheat more at altitude since the air is thinner and less hp and stack cooling is available at altitude.

Fixes appear fairly simple for GM: upgrade the exhaust to increase flow and eliminate backpressure through ECM direction to the turbo or something similar; apply sufficient air deflection techniques to get the stack flowing; and install electric fans (2) controlled by the ECM to manage ECT's more precisely and pull BTU's down/away from the engine compartment.

Just my thoughts today. Looks like it is going to be a busy posting day on the DP. TxC, where ya at dude? JJ

JJ

I think if you show that fittings blowing off, happens consistently with the highest IAT's occuring, sure, back pressure. Lowering IAT 100 degrees should bring down EGT's 200 degrees, though airflow over the CAC is the true reducer of charge air. Just that better CAC flow is going to also be lower IAT. Like fingers says, high IAT is more of a symptom (effect) of the other problem.

I keep correlating to IAT because we can measure that easily and reliably, not so with entry and exit charge air at the CAC.

I can tell you, GM will never go for electric fans, nor do I really think that will solve much, if inherrent flow is restored in a good front end body mod. Right now the fan is doing a job it was not intended to do. Fans are AUX cooling, not a replacement for good design. I still don't like the T-V design, but we may be stuck with it. Once you have good hi-way flow, you'll never hear the fan again till you slow down (empty vehicle) where it is suppose to compensate for lower flow of slow speed. The loaded vehicle will have more power (25HP-100HP), more of the time, and of course the resultant mpg improvement. The engine and tranny will last much longer, no more steep ECT thermal cycles fatiguing metal.

But Ponder this:

Winter: -In 40 degree weather, it takes 30 minutes just to get a reading on the ally. I have to drive 20 minutes just to get the first stat to open up, or the old Edge to kick in. IN PHOENIX! The same flow improvements will lower tranny temps to such an extent, that a bypass may be needed in the winter to keep fluid temps up in the operating range. If you have an oversized tranny cooler in the north, with no bypass built into it, look out. Everyone mayl suddenly find they need to put on the front end bra just to have heat in the cab. These things will be possible consequences we haven't digested yet. So we may want to consider flow solutions that can be undone or blocked.

Both the CAT and EGR create backpressure. If the VVT is pulling too high boost as suspected is it possible to overload the CAC, IC and exhaust and create excessive backpressure. I may not have said that right, but hopefully you get my drift.

Several pages back one of the guys that was overheating also had the IC coupling blew off. The dealer said they had seen this on several LLY's. Someone else previously posted that there IC coupling blew off while towing. Just a coincidence, maybe. I'm just putting out some possible scenarios on what is happening to put the LLY into overheat mode.

Stupid question: is the tranny cooler pre or post radiator? Agree we may have some issues with colder temps. JJ

is the tranny cooler pre or post radiator? Agree we may have some issues with colder temps. JJ

Post radiator, then back to tranny

We will have to cross the winter driveability issues in 6 months.

I don't think we have to flood GM with a class action, most stated have Lemon LAws - we can just flood them with Lemon Law letters. I for one am not goint to wait. I will file a lemon law letter the minute I take my truck in three times ( per the law) and the dealer does not fix it ( which he will not be able to ). This for me is a saftey issue, I can not drive across 120 plus desert highways with the air conditioning off, and the vehicle overheating, potetially shutting down and leaving me and my family starnded.
Not me folks. I saw a highway patrol officer putting a family, with car seat and all in his car because they were staranded and he could not gamble on when help would come so he was keeping them cool in his car - temps were 122 on the mirror.
Besides 50k for a vehicle that over heats, not in my life time.

They will be looking at the overheating poll today.

A Class action takes time, publicity does not. They don't want the bad publicity. Unlike KB I feel as though video of a truck on dateline or an article in car and driver or motor trend or truck trend is very motivating to GM.

They claim to be on it, but we need faster action than this, because they SAY they are on it but show me one person with the problem that they cured.

Fix what you sold or watch the sales go to the tank.

.

You can add another overheater to the list, it's my buddies 4.5 2500HD LLY, towing a 6500 lb boat through the desert with 118 OAT on the mirror. Ran 210 on the flats and small inclines but when we reached the big hill, 16 miles of 6 to 8 percent grade it got hot, was a needle width below the red and the DIC said engine coolant hot. Turned the A/C off and reduced speed and the temp dropped to about 230 for the rest of the climb. Got to the top and the temp returned to 210 and remained there for the rest of the trip.
This is not what I wanted to see, as I will be towing a 12,000 lb 5er in the same conditions in about 2 months with my signature truck.

When GM says they are working on it, how long would you expect it to take for them to engineer a fix?

When GM says they are working on it, how long would you expect it to take for them to engineer a fix?

Hmmmmmm lets see, when we made them aware of it last year they said they were looking into it. Here we are a year later and they don't have a fix. So you tell me how long they should get.

.

TxC,

When are you speaking with them today?

I already did this morning. I was given another name and number by powertrain to someone in engineering, got voicemail, they want us to hold up but they haven't even identified the problem. I told them we need definitive action, talk hasn't done anything, and it appears only a lawsuit and media attention will motivate them. They don't want that, can't blame them, but damn they need to act on this or there is no choice but to make a fuss with the media and courts.

.

You can add another overheater to the list, it's my buddies 4.5 2500HD LLY, towing a 6500 lb boat through the desert with 118 OAT on the mirror. Ran 210 on the flats and small inclines but when we reached the big hill, 16 miles of 6 to 8 percent grade it got hot, was a needle width below the red and the DIC said engine coolant hot. Turned the A/C off and reduced speed and the temp dropped to about 230 for the rest of the climb. Got to the top and the temp returned to 210 and remained there for the rest of the trip.
This is not what I wanted to see, as I will be towing a 12,000 lb 5er in the same conditions in about 2 months with my signature truck.

vote for him in the overheating 10k+ poll

.

How likely is it that the GM Powertrain folks are going to fess up to the GM Head Shed that they %^&^&*( up the LLY? People are usually pretty hesitant to cut their own throats. What I am saying is we may be talking to the wrong people. While theyy have all the technical knowledge and know-how to run this to ground, they likely aren't too excited about having to "fall on their sword" and take ownership of this problem.

TxC, maybe we need to go to corporate on this. Ultimately they have the power to reign in all their departments, push ego's and loyalties aside, and get er' done. Other thoughts?

KB, I took a drive at lunch with my modified front end. BTW, Mama JJ commented last night that it looks ghetto. lol What I have noticed is the ECT's drop even faster than when I removed the plastic shield. For example, when I hit the exit ramp on I95 doing 70mph the ECT's are 198*, less than a half mile coasting they are down to 190*-192*. Unusual considering there are still BTU's coming out of the block from the hard run. Tranny temps are staying around 160* with outside temps at 95* at 70mph. So I am noticing some improvement, just not enough.

I'm checking into the air deflector that goes on the 1/2 ton's. The dam that holds the fog lights comes down fairly low, another 2" might just do the trick. Busy day! JJ

I'm checking into the air deflector that goes on the 1/2 ton's. The dam that holds the fog lights comes down fairly low, another 2" might just do the trick. Busy day! JJ
JJ, I ordered mine toay- should be in the end of week. I am towing this weekend so I'll give'r the o'l acid test. Hope between that and the intake mods we're on the right track.

I am on the phone now with another GM person talking her through the website

She probably works nights, working a 900 number. Say hi for me.

Shartrain, is that you baby? lol

Sweet talk her TxC, you sweet talking devil you! JJ

The majority of the Posts on this thread (2043 post) address the "Overheating LLY" as a Problem to be Solved.

The Extraordinary Effort of All that are involved here to, identify Problems and Postulate Solutions is Impressive and valuable to us all, I thank you individually and collectively.

I have an LB7, the stack flow and IAT issues are equally applicable to my truck, IMO.

PLEASE, let’s not make their efforts more difficult by Posting extraneous non focused issues Here.

There are other Threads for: "Buy Back" (45 post), "Polls" (107 post) and "Class Actions" (4 post) or start a new thread. Lets stay on Track.

This is my opinion, had to say it.

Idahofox

Uh KB, you don't think TxC is going to show her this thread, do you? Gulp! lol JJ

There are other Threads for: "Buy Back" (45 post), "Polls" (107 post) and "Class Actions" (4 post) or start a new thread. Lets stay on Track.

This is my opinion, had to say it.

Idahofox

Agree. Perhaps it is we that should start a new thread, this one is unnavigable anyway.

Oops!

Start it KB, I'm with you.

I'll help collect and xfer "DATA" to a new Thread.

I'll follow your Lead.

Idahofox

Uh KB, you don't think TxC is going to show her this thread, do you? Gulp! lol JJ

If she starts at the beginning, we have 6 weeks to get out of town

Even though this thread is long it is nice to be able to search just this thread and find data previously posted versus finding all the other posts somebody made and have to weed them out. We're so close to nailing this problem, what's a few more pages going to hurt? Besides we are catching up with the "In a Word" thread that has over 6500 posts. Bragging rights! JJ

I just wish we got someone's attention without killing the $$ value of the trucks- I like to have new every 3-4 years but not take a beating at trade time. The general impression I get for all is we like everything :cool: about our truck but can't trust it to get us from A-B with out getting hot and in some cases making us walk. The fun factor, for me anyway, this past vacation was nill because I had a truck that might let me down when I need it the most. Thankfully it did not, just made me very crabby Censored - just ask the better half.

TxChristopher, Do you think it would help if you named names and phone numbers of the people you talk to at GM so each of us that had the overheating problem could also call them and explain the situation that caused our overheat condition? I'm thinking that if one Engineer or Engineering group had all the facts straight from us perhaps they could solve the overheating issue quicker. As an example maybe if they checked the vin numbers and found that all the over-heaters were built at the same plant and time, that might point them towards a faulty part or vendor.

If she starts at the beginning, we have 6 weeks to get out of town
:funnypost:grd: !

Shartrain, is that you baby? lol

Sweet talk her TxC, you sweet talking devil you! JJ

No that wasn't her, registered under her actual name. She is now in the process of taking this in, she was somewhat overwhelmed with it. She said she will see what is being done and if needed will go to the head engineer on it. We will see.

.

Engineering Notes keep us from "Reinventing the Wheel".

A summary Document keep us from "Reading All the Notes".

Maybe a "DIY" article down stream?

Idahofox

Ordered the materials today and talked to my buddy about getting it laser cut. Man I love his laser cutter. I should have 3 prototypes available by the end of the week.

I showed her this thread, the overheating poll, and she saw the lawsuit ones and buyback ones as well. She seemed suprised, genuinely, makes me wonder what the powertrain guys have been doing.

.

Powertrain guys have been looking for other jobs before GM fires their a$$e$ for screwing up their bread and butter machine! Someone in corporate needs to be aware of this. Was she in the Powertrain Division as well? Don't need the "Corporate Shuffle" if you know what I mean. JJ

No, not powertrain, engineering communications or some crap, deals with all the trucks and is the PR face for engineering, sits in on the meetings and such for engineering direction.

Says she works with the assistant chief engineer on the duramax, and if she can't get anything on the surface she will go talk to him.

.

I spent a couple of hours at my dealer today. He is going to call GM today on my overheating. Bear in mind I went thru this last year and was told they knew they had a problem and they would fix mine when they found out how.

On a side note I walked around a little and the only air damn I could find was on a new Suburban. It is a 2" extension of the lower plastic under the bumper. Part # 15224193. list $24.63. I will have one Thursday.

Rick, have you plugged all the holes and avenues for air to get around the stack? Particularly the POS flap under the tranny cooler has numerous openings for air to get around it and not forced through the stack. The front end of these trucks has a major air hemorrage.

$24.63, my dealer is charging $35! That's what having a fleet account will do for you.

Fingers, anxious to see the final product. BTW, did you have a chance to pull pressure differentials with/without that plastic plate underneath the truck. Sorry if you already posted that, I didn't see it. Things have been moving quickly the past few days. JJ

A couple of interesting test runs today.

Blocked most holes in the radiator bulkhead. Saw no detectable difference in differential pressures. Did find the Air box was hot when I opened the hood, so I undid the blocking. Air box was much cooler for later runs.

Extended the air dam 2 " with some aluminum sheet. Differential went up a whole 0.5 iw from base dam test maybe more at 50 MPH. Dam seemed to be more effective at lower speeds. Test aborted. Aluminum came loose at 75 MPH. Pulled over and removed. I suspect the distance from the bottom of the dam to the ground is a key factor. This would track with some other info I have. Lower is better. Base dam is ~9-10 inches from the ground.

I have not removed the splash shield for two reasons. One, I don't think itis an issue when running the dam and two, I can't get to the bolts without removing the upper ghetto.

I too am not looking forward to a fight against GM or exposing this defect that our trucks have. But let’s be clear, unless any or all of want to switch brands and sell our trucks I firmly believe we must force GM to resolve this. They have the absolute means and equipment to get a complete and full resolution of this. No disrespect intended to anyone that has been working very hard to get this done, but only a manufacturer has all the required R&D, wind tunnels, blue prints, etc., to this product to make a decisive and complete repair of this issue.

Market conditions on resale will always fluctuate with any product, just as they are now with $10k discounts on new models. How much do you think these trucks are worth when you can get a new one with that type of discount? With a complete repair of this issue any temporary loss in value will quickly rebound once a resolution is made. If for some reason a resolution of this issue is not available, then our trucks will go the way of the Ford Edsel, the Audi 5000, and countless others. If that is the case then a class action law suit is the only remedy.

Let’s face it, the difference between a good company and bad company is how they react to their customer’s needs. The proactive company comes out of just about any dilemma, but the reactionary company’s die by their own deeds.

Finally, I want to be clear, other than this issue I do not want another brand of truck, I love this truck, other than this issue. I have gone through one buy back, and it was the first one of my life, and I do not want to go through another one. We all spent nearly $50k for these pickup trucks, and we need to be made whole!

I have messages for both the law firm that was recommended and I also left a message for Lee Thompson at Dateline NBC. In one week if Dateline does not contact me or any of us, I will try another network. Any and all local consumer reporters both print and media should have an interest in this. For those of us in various parts of this great country, I recommend highly that you contact these people and try to get their interest; I will continue to do the same. Magazines may or may not be responsive, as their only source of income comes from the manufacturers.

We are all sick of this problem lingering on. If you have numbers to GM were people listen lets all give them our input. My 04.5 was purchased back for many reasons but one was overheating. Although my 05 has not overheated it has not pulled anything large. Lets get them moving. If the media gets hold of this our trucks will surley loose value but what good is a truck that can't be used for it's intended purpose. It will take all of us to push GM to a fix!

A couple of interesting test runs today.

Blocked most holes in the radiator bulkhead. Saw no detectable difference in differential pressures. Did find the Air box was hot when I opened the hood, so I undid the blocking. Air box was much cooler for later runs.

Extended the air dam 2 " with some aluminum sheet. Differential went up a whole 0.5 iw from base dam test maybe more at 50 MPH. Dam seemed to be more effective at lower speeds. Test aborted. Aluminum came loose at 75 MPH. Pulled over and removed. I suspect the distance from the bottom of the dam to the ground is a key factor. This would track with some other info I have. Lower is better. Base dam is ~9-10 inches from the ground.

This brings up something that might interest everyone here. My 04.5 3500 2wd was one of the first to record overheating issues. I had thought that a reflash had cured the problem. Interesting enough around the same time as the reflash came out I turned the truck over to my son and bought a new one. He did not like the truck sitting so high, so we spent a weekend and lowered the truck 2 1/2 inches. Might be a coincidence, but interesting, none the less.

It had recently started overheating again, and I thought we were in trouble all over again. It turns out it was just a dirty radiator. We wash them often, but that is not enough. The mechanic at the dealership blew the radiator out with air, and the amount of dirt that came out was amazing.

Fingers, I asked because Rick's runs would seem to indicate there was an improvement with that shield removed. The air dam may negate that though, way over my head. I understand not wanting to take it off if it is a royal PITA with the ghetto dam installed.

Rick, the front deflector extension you are buying should allow you to take that plastic shield on/off fairly easy so we can compare the results. Being that it only drops down about 2" question is will that be enough to make a significant difference? We'll see. JJ

Powertrain guys have been looking for other jobs before GM fires their a$$e$ for screwing up their bread and butter machine! Someone in corporate needs to be aware of this. Was she in the Powertrain Division as well? Don't need the "Corporate Shuffle" if you know what I mean. JJ

Yeah, don't want the shuffle either. They have to know that this isn't going to quietly go away.

GM should be firing people on this, they pay people good money to NOT screw up like this.

.

On a side note I walked around a little and the only air damn I could find was on a new Suburban. It is a 2" extension of the lower plastic under the bumper. Part # 15224193. list $24.63. I will have one Thursday.

The one I ordered is part #10386198 $27.00 and is off the 1/2 ton trucks, not sure why 2 #'s but mine will be here Wednesday PM. I'll post before and after photos.

The 1/2 ton air dam may not be long enough to give you the proper -P under the truck. The D/A has a 2" body lift to clear the ally. Fingers is on the wright track. It needs to be as low as possible to achieve the best relsults.

How do you know when the fan is running or not

Oh you'll know, it is very loud! :eek: Have you towed with your vehicle yet? :confused:

cwest, hopefully for the small investment it will provide some negative P. Gotta go see the boyz on the Overheating Solution thread. JJ :)

Killerbee made a post a few pages back and asked "Can you get your fan to shut off when you hi-rev the truck for 30 seconds?"
HUM!!!!!!!!!
I am almost 100% sure that happened to me 2 times the last time it was running real hot. As I floored it and it down shifted to 3rd the RPMs went to about 3200 and it got quit for a couple seconds and then real loud again?????????????????????
Anyone know anything about this?
Dan

anyone having temp problems with the allison? My 04 with 49k started today towing about 8500# at 94 degree's outside. Engine temp was normal and fluid levels were good!

Killerbee made a post a few pages back and asked "Can you get your fan to shut off when you hi-rev the truck for 30 seconds?"
HUM!!!!!!!!!
I am almost 100% sure that happened to me 2 times the last time it was running real hot. As I floored it and it down shifted to 3rd the RPMs went to about 3200 and it got quit for a couple seconds and then real loud again?????????????????????
Anyone know anything about this?
Dan

short cycling. The clutch engages when hot, disengages when cooled, 205 (air temp) it is suppose to come on. The control input (on/off) is the temp of the air flowing past it. The hi rpm cools the clutch by pulling a butload through the stack, the inner stack flow drops below 200 momentarily, disengaging it. Temps shoot right back up because the stack members are still heat quenched, and the low flow allows the cooling air to get real hot again, reengaging the clutch.

Commentary: If properly designed, it would stay on till the rad was below 205, and have nothing to do with air temp.

lynnwright, and???? On edit, where's my manners? Welcome to the DP!

KB, your on a roll this morning. My fan clutch will engage when I'm slowing down to a stop with the 5ver in tow. When I start to move again it will roar for a few seconds then disengage and free spin. JJ

Lynnwright - make sure you are using the Tow/Haul selection when towing (if you are not already). This will help keep tranny temps in order (by locking the torque converter in gears 2 through 5).

Alan

Delar called today- zonerep iscomming in next wekk want me to bring in my truck and talk to her. Told'em hey- Talk or gripe?? LOL I'll let you know what if anything pans out.
On another note, while I had them on the phone I asked about adding the exta air dam and they said hang on- came back and said they'd spring for it- so ..... Maybe they are listening???

My dealer offered to sell me a hood at cost today. I told them I wanted to put louvers in it. I will try to get them to pay for it!

I have a appointment Wed. afternoon to drop the truck for the new radiator , I will be going to LA this weekend if all goes well with the install , As hot as it is it should be a OK test run to see if the new Rad has a effect. I will update as we go and post pictures , I removed my electric fan , I want to start as stock as Possiable ,this will just be with exhaust and a K&N filter otherwise stock. I could have gone in today but they are getting me a car to drive in case it gets to be extra time.

Blizzardplowman,
My Dad owned a GM Dealership some years ago. I can tell you it seems unlikly that GM will put any part on a vehicle that wasn't designed for it. The process has to go through Engineering, Federal Highway Safety, EPA and be signed off by all before they will do something like this. Sounds like someone over stepped their bounds or just wanted you to go away. Good luck, We will see what happens

Rick, I will be mapping the hood for pressure this weekend, for vent siting. I will post a hood pic with all the numbers.

Carhauler, after what we have discovered about flow, do you think another rad will help?

Do you have any pics of your elec fan? I was not aware of this, interested in what you did.

Blizzardplowman, are you talking about the OEM 2" strip? Like $28-$30 IIRC. If so it shouldn't be an issue. JJ

Rick, I will be mapping the hood for pressure this weekend, for vent siting. I will post a hood pic with all the numbers.

Carhauler, after what we have discovered about flow, do you think another rad will help?

Do you have any pics of your elec fan? I was not aware of this, interested in what you did.

Mapping the hood is going to take a while. ):h

I think the rad might be too small.

Blizzardplowman,
My Dad owned a GM Dealership some years ago. I can tell you it seems unlikly that GM will put any part on a vehicle that wasn't designed for it. The process has to go through Engineering, Federal Highway Safety, EPA and be signed off by all before they will do something like this. Sounds like someone over stepped their bounds or just wanted you to go away. Good luck, We will see what happens
I've been buying from them since '83, 40+ vehicles, hope they treat me better than that. It's not the dealer- it's the wimps at GM corp. that worry me- the bean counter have taken a great truck and made it OK. Our 01,02 trucks are 2x the truck that the 05's are in build, and little features.

Blizzardplowman, are you talking about the OEM 2" strip? Like $28-$30 IIRC. If so it shouldn't be an issue. JJ
YES.
True- but if they do it at least they are admitting to an issue as far as getting it and installing it.

Blizzardplowman,
My Dad owned a GM Dealership some years ago. I can tell you it seems unlikly that GM will put any part on a vehicle that wasn't designed for it. The process has to go through Engineering, Federal Highway Safety, EPA and be signed off by all before they will do something like this. Sounds like someone over stepped their bounds or just wanted you to go away. Good luck, We will see what happens

You really believe that? No, it does need to be evaluated, usually by engineering. They are cognazant of the applicable Safety and EPA rules. If the change does not impact compliance, it can be approved on the spot.

I feel sorry for you guys. I have been following this thread as well as the others, and all I can do is shake my head. We had to take our new 5er in for some service yesterday, outside temp was anywhere from 102-104...we are having a heat wave in Colorado this week. Anyway, the new rig probably weighs over 11k. Had the A/C set for 68 on my side, 70 on the wife's side (dual climate control) and the engine temp never moved the whole way, just sat about a needle below 210. Tranny temp was right around 200. Had lots of rolling hills, some steep, and a combination of stop and go traffic in some of that trip. Engine fan cycled but never loud enough to over come conversation...more like a hum than anything.

Yes, I have an 03, but I feel sorry for you guys in that you could not do what I did yesterday without having to turn the A/C off, or watch your engine overheat before your eyes. I know this really doesn't help much, but I hope GM can fix this problem and bring confidence back for you guys. They should be able to do what I just did yesterday and not break a sweat (you or the truck!).

Keep your chin up guys....

Bob

You really believe that? No, it does need to be evaluated, usually by engineering. They are cognazant of the applicable Safety and EPA rules. If the change does not impact compliance, it can be approved on the spot.

And what zone paper pusher is going to stick their neck out and make that detirmination. The only thing they know is how to smooth over issues and try to make you go away. Most are spineless. They have to check with their bosses.

I feel sorry for you guys. I have been following this thread as well as the others, and all I can do is shake my head. ...Keep your chin up guys....

Bob

No wait...don't go!

Bob,
There is something you can do. With all your good fortune, how about a contribution? We'll start a new fund for testing mods. You can "cut the ribbon". We'll call it the "4x4man foundation for homeless overheaters"

In fact I think anyone with an LB7 who brags on this thread, should have to anti-up $100. All in favor?...

Sorry, bob, nothing personal, just happened to be you.

Seriously, thanks for your encouragement.

Years ago back in the 60s and early 70s there used to be area ASMs (Area Service Managers) most of them came from the trenches and knew their product. If a dealer had a problem with a vehicle he would make sure the customer was there at the dealership the same day as the ASM. Once the customer got at the dealer the ASM would put his coveralls on and work on the vehicle to solve the problem. This was a great policy because it made the customer feel like someone cared about their problem, If he couldn't solve the issue he would rattle cages at corporate until he got an answer. Now we just get paper pushers unable and unwilling to make a big decision that might not be popular with corporate. Sorry if I sound a little cynical

I don't claim it is easy, but the goverment is not the hang up.

After watching this post for over a year it sounds to me they know what the problem is but it would be to costly to provide a fix. They will quietly make a design change that will fix the problem and that will be the end of it. All of us that are overheating will be stuck. Why else do some people say that powertrain knows they have a problem and are working on a fix yet other posts say that when dealers contact powertrain they say they are unaware of any issues. WHO'S JERKING WHO AROUND! You better believe that with the amount of clutch, radiator warrentie claims they know they have a porblem they just don't want to let the cat out of the bag. Rest assured they have tested the Fingers getto air dam, the removal of the splash sheild and done wind tunnel testing they just aren't saying anthing. THE FIX IS TO EXPENSIVE! To try to retro fit all exisiting trucks is cost prohibitive. A few buybacks and a little bad press is cheaper.

KB- No offence taken. I understand everyone's frustration with this overheating issue. The good news is (for me at least), I wasn't bragging, so I am not out $100!! :D Now if you needed an extra truck to go down to GM's front door and do battle, count me in as I support our fellow "place" members whenever I can.

Being as that I don't have an LLY, I am unable to contribute testing, or even theories like others have, so back to lurk mode I go!

Bob

GMs attitude toward this particular demographic of buyer is insulting. Typically, owners of these rigs make thier purchases based on a criteria to meet thier needs. This usually involves a fair amount research based on the manufacturers claims, specs, and many times ALOT of previous experience with this style of equiptment and its associated possible problems and ramifications. Many of the members on this board are ten times sharper than the typicall mechanic at a GM garage, or even the service manager.

As a group we typically are used to rolling up our sleeves, grabbing our tools and perfroming the neccesary task to SAFELY and correctly make fixes our families will depend on. We understand the vital importance in NOT doing band-aid fixes when pulling our trailers or performing business task and chores. We go to great lengths to avoid the problems years of experience have taught us about "weak links".

Of all the maladies to have with a vehicle designed for this market "over-heating" because of bad engineering is not one easily fixed. It is a HUGE safety and security problem for many whose families and businesses RELY on these. Ultimatley it will kill the resale and confidence in our products and WE, not GM, will be stuck with the tab. After all, GM already has thier money, and is already creating the marketing for thier next sale. History has repeatedly shown they need to be "pushed" to do what is remotely fair to the consumer. Frankly I'm a little surprised with the cost of these trucks the outrage is not louder.

Killerbee, I don't have any pictures of the fan , I can say its help was marginal at best , best thing it did was make the air ice cold in traffic and shut the engine fan down a little more often as well in slow speed situations , I removed it for now . I believe the Rad. will help but not cure , the main thing is they are doing something and once they start the marriage begins! and I am in a much better position ,and if they find a fix and aknowledge the problem and fix they are stuck with it , being this is such a erratic problem I don't believe it will become a recall , it would be stupid to spend the $$ for GM , but it will be a TSB for the ones that have the problem and complain.I hope to have it back late today or tommorrow and I will report in and Post pictures .

It is good to see you still at it.

A few people have mentioned the idea of recirculated air -- hot air
being blown out under the truck but then being sucked back into
the grill. This is sort of a bow-wave effect.

This one is easy to check, using old-fashioned tell-tales, a front
hitch and a video camera.

Mount a set of tell-tales on a T using a front hitch. I think 3 layers,
say at 8", 16" and 24" would be enough. Use the full width of the
truck, say 8' worth. Have the array stick out about 4'. Put a tell-tale
every 6" or so.

Use 1/2" EMT for the stringers, then 40 lb test fishing line for the streamers. Go down to WalMart and get pre-cut carpet-hook yarn,
say in bright red. Tie them all on, and glue with something sticky,
like Duco Household Cement, or Amazing Goop.

Film this array while driving; you can have somebody on a motorcycle
drive in front (ok, you need 2, one to ride and one to film) or mount
the camera on a pole in front of the tell-tale array.

If there is any recirculation, it will be easy to spot.


A while back I suggested a NACA duct in the fender. The idea was to
induce cool air, using a duct more efficient that what is currently in
place. I do not want to hear (again) about how such a duct would not
be efficient -- in this case we do not care about absolute efficiency, but
relative efficiency. A NACA-like duct would be WAY MORE efficient than
the hot-box in the fender. This is still a good idea if anybody has a spare
right fender to play with.

Mapping the RELATIVE pressure zones in the front of the truck would be
pretty easy. Just use a differential manometer and some cheap rubber
tubing. We do not care about the absolute pressure, just the relative pressure. Use a plastic J tube and colored water. Put it in the cab
and use a digital video camera to film it as you drive. Each time just speak
the information about the test conditions as you drive.

carhauler,

Dumb question, will the new rad be the same size as the old?

Fingers , I will know soon , I assume it will be alum /and larger cooling capicity ( as size of install area permits ) and likley a different style of coolant tubes , they tell me today to get it back but I am not counting on it till they call , God knows I like the Cavalier I am driving!! I looked at a Hybrid Silverado while I was there , nice electric fan set up ,I would like to know the CFM of the engine fan compared to the 2 electric fans. They pulled alot of air and were very quiet.

The CFM of an electric cool package at full throttle would be about 1/2 of an engine driven fan package CAN be. Just to let you know

LJD

Killerbee, I don't have any pictures of the fan , I can say its help was marginal at best , best thing it did was make the air ice cold in traffic and shut the engine fan down a little more often as well in slow speed situations , I removed it for now . I believe the Rad. will help but not cure , .

A pusher fan, I didn't realize. Tell me why you think another rad will help? If there is insufficient airflow for this one, how would a larger one (assuming larger) do any better?

Please take side-side pics, and pics of everything if you can.

Frank EP,

how about headin over to the other thread, if you haven't already.

I don't honestly know why Chevy is starting with a Rad. Chev Racing is involved with the build on the rad ,so at least someone with some smarts is involved ,the biggest deal here is they (GM) are doing something! mine is not to look a gift horse in the mouth ,advantage being is once they start they have to continue to resoulution. On the electric cooling ,everyone seems to think the fan on the engine is so much more capable, I don't know but BeCool make electric set ups that will cool a 1,000HP , maybe actual CFM vs flow and elimination of robbing HP to turn it makes alot of difference. The big trucks ( semi's)are going to start using electric fans so they must work.I believe the fan is not the problem ,for what its worth I believe the combo of Rad/Intercooler/and Mostly!!Getting the hot air out from under the hood will be the cure. I am not a engineer or expert ,but I have always been good at "a feel" for whats up and I would put money on these 3 thing together will be the fix.A huge problem here is once it starts overheating the systems can barley keep up let alone bring the temps back down ( this is where the Radiator /fan is of large consideration) as I said ,I don't know why they picked a Rad. to do first ,but here I sit waiting for the call from the dealer like a teenage girl waiting for the football captain calling for the Prom. OH WELL!!

A pusher fan, I didn't realize. Tell me why you think another rad will help? If there is insufficient airflow for this one, how would a larger one (assuming larger) do any better?

Please take side-side pics, and pics of everything if you can.

Because the problem isn't insufficient airflow, according to 60% or so of the trucks out there. There is a large contingent that run hot, but the latest data indicates the heat is coming from the engine. The stack is more than sufficient and airflow is more than enough when the engine is not saddled with this rogue, unanticipated heat source.

The only possible way it could be insufficient airflow is if 100% of the people that tow heavy and say they do not get hot are WRONG.

The Solutions thread is great, it is a more focused idea group than the discussion here, but the best solution is not the ghetto dam or various airflow tricks or added fans or tranny coolers. The best solution remains and always will remain to identify and correct the problem that causes the 40% of the trucks to overheat.

Going by Ricks experience it would seem the problem is bad castings in the cylinder heads. So how do we verify that?

Are the heads side specific? If not, it may explain why some trucks are more prone to getting hot so easy, they drew two bad castings out of the pile. Call these the "overheats flat ground" group. The guys that get hot in the hills perhaps have one bad casting head, call them the "overheats w/hills" group. Then there are guys that didn't get a bad casting, call them the "tows everywhere never gets hot" group.

There are 60% or so of them out there, proving all the time that airflow, radiator, heat rejection etc etc etc are right on with the truck.

Unless 100% of them are wrong. Place your bets ......


Shields up. :)

.

I don't honestly know why Chevy is starting with a Rad....something!...why they picked a Rad. to do first ,but here I sit waiting for the call from the dealer like a teenage girl waiting for the football captain calling for the Prom. OH WELL!!

:funnypost lol

TC- I agree to a point, but then I don't know what is wrong either. The whole thing in a nut shell is it could be a comebo of several diffrent things and thats not the point, point is I paid for a truck do do as advertised and it don't . I just want a proper fix. Now as I said before, a new fan clutch helped, weter wetter helped, the trans cooler helped around town, jury's still out on the western trip due to how hot everthing else got, and the air intake mods helped, truck went long before the downward trend. I don't know how we tell if its casting ect, unless someone talks GM into buying heads(unlikely) or What we are trying helps. I hope to get my hands on an 06 soon, I can take it for a 24hr test drive, but the dealer I use won't have one for 2/3 weeks, then I'll be taking measurements etc to see if we can figure out the differances. ok sorry for the long post.
:grd:

I think that GM is doing what many of us are doing: trying to OVERCOME the problem. It is cheaper to pay to have radiators made and installed that can drop another 20-30 degrees heat off for a few minutes than to go into the motor and replace cylinder heads or turbos for example.

It's all about the money in the end, sex or money, and if they can get by spending less then they will.

Blizz we all have diff views and that fine, but personally I don't buy such a common problem (at 40% it is fairly common) being a combination of things. If the setup was that weak then we would see clear 100% failure rate. Yes there are some things that could be improved upon, and I am sure cost was a factor in he design, but again, 60% of the trucks have NO ISSUE AT ALL.

.

I bet its the new style heads that are part of the problem. Poor water jackets?

I bet its the new style heads that are part of the problem. Poor water jackets?

Thats where my money is, especially after Rick had a truck that DID NOT get hot, but the engine cut loose and the heads and turbo had to be replaced, then voila! a truck that DOES get hot.

Tough love there but there are only so many scenarios that fit that one. He has shown that the controls are in line for the boost on that engine, so it is either the turbo or the heads. My money is on the heads.

.

I would be not surprized by the fact 60% of the trucks do not really tow, My truck runs fine in any temp at any load until I pull a hill , I am not trying to stir the pot but most people don't do what RDL/myslf and some of the others do , we are by far in the minority , I am not saying its not a problem that should be corrected by GM but it seems we are up to about a million reasons and rising everyday,its hard to take a accurate pole with the situation at hand , recreation use/business use/light loads /heavy loads/aerodynmic /VS pulling parachutes How can we be accurate? I for one am going to let GM beat thier head into the wall for awhile and see what falls out.

I would be not surprized by the fact 60% of the trucks do not really tow, My truck runs fine in any temp at any load until I pull a hill , I am not trying to stir the pot but most people don't do what RDL/myslf and some of the others do , we are by far in the minority , I am not saying its not a problem that should be corrected by GM but it seems we are up to about a million reasons and rising everyday,its hard to take a accurate pole with the situation at hand , recreation use/business use/light loads /heavy loads/aerodynmic /VS pulling parachutes How can we be accurate? I for one am going to let GM beat thier head into the wall for awhile and see what falls out.


Nooooo I am talking about the results in my poll "Overheating LLY's - 10,000lbs or more"

The poll was designed to target heavy towing, read the conditions of the poll.

I would say way way WAYYYYY more than 60% of these trucks never EVER tow heavy. Thats a given, too many concrete cadillacs out there. But the poll focused on JUST people that tow heavy, and the numbers have been holding around 60-40 from the start of the poll to now and are unlikely to change.

.

Tx- Not disagreeing just don't thinkthe poll is 100% due to the fact heavy - 27k will make mine run hotter 220/225 but heavy and high wind will make it cooook itself. Just like RDL, 28k and tall/wide make it hot. FWI If I load up the GN and my 44' boom lift- 27k +/- depending on fuel load, I have yet to get it to 250 like I can with the fifth wheel at 23k when it was empty, then prior to the fan 250 post fan 235. Just tyring like everyone else- po'd that the truck isn't right. Keep up the good work.

Tall and wide up the power required to go the same speed so they naturally work the engine harder, as does wind, so you are pushing it a little more than if you had same weight but were more aerodynamic. The "little more" brings the issue to the forefront.

Ya got the one bad head LOL!

Huntsalot has 2, so does Wallbanger.

.

Funny that's what my wife keeps telling me. Two bad heads go figure!!

Ok so I'll go with that thought- how do we prove it? Bet we can't and the fix we get " like carhauler said' is a bandaid. Back to the same old chit- keep trying untill warranty is up then, sorry to bad.

Funny that's what my wife keeps telling me. Two bad heads go figure!!
I wasn't going there, but... :funnypost ):h

You didn't get this idea from me, and of course it would suck if such a thing happened, but wouldn't it just SUCK if somehow your valve cover came off and a retainer somehow came loose and a valve fell off into the cylinder and the valve cover fell back on and the truck ran around for a while after that until that mystery valve did enough damage that the head would need replacing? Under warranty of course.

The hard way to get some free R&D from GM but if it were me with the overheating problem and they wouldn't do any f'ing thing about it then I wouldn't have a problem one having the above described bad luck.

.

Get some thermal shots with the IR temp thermo, see if one head is hotter than the other same point to same point. Write down the locations and keep track all over it, especially near exhaust ports where the classic overheating sources come from on heads in the past. Its messy but you can run the truck with valve covers off and cardboard to block the oil so you can check the surfaces while running for inconsistancies. Oil cleans up anyway. Again focus around the exhaust ports and valves.

The hotter head is the unlucky one that drops a valve.

.

I hear ya, but I think I'll just give'm 4x and call the lemon squad and be done. I don't need to get more po'd than I am . But I will have "demoed" a 06 first. Just to see how she runs, or if its no change.

Tx, it may not be important to understand, that poll is not statistically viable. Anyone with an ounce of economic sense would laugh. I wouldn't want to remark this there out of respect (and I don't need any more green friends). You are polling only enthusiasts, who are likely to be doing things the general population on the whole is not doing. I'm sorry, but this really needed to be said in a constructive way, I just couldn't find the right words.

The basis of your statement above is equally laughable:

"Because the problem isn't insufficient airflow, according to 60% or so of the trucks out there. There is a large contingent that run hot, but the latest data indicates the heat is coming from the engine. The stack is more than sufficient and airflow is more than enough when the engine is not saddled with this rogue, unanticipated heat source.

The only possible way it could be insufficient airflow is if 100% of the people that tow heavy and say they do not get hot are WRONG."

Gremlins? This explained what?

" the heat is coming from the engine" Really? Ya think? Isn't it time to open your mind. I think a year was enough time to lose this argument. I'd like to see you win it, but

"airflow is more than enough" have you been living in a vacuum? Fingers one run disproved that. That one run with an air dam represented more progress on this issue than the 1800 posts before it.

60/40 on a poll?. We all know what it takes to overheat, nary a mention of any severe conditions in the poll. A guy pulling 11K in a county that doesn't have a 1% grade, or ever sees over 90 degrees, bragging about his 210 temps at his speed limit of 55 mph. c'mon. The poll is not useful in explaining anything. BUT, if you get a guy, who says he just doesn't overheat (just one) to go over to the other guys (who does OH, someone like rick, pedal down) place, pick up his load and pull his OH conditions. If you can do that, I'll eat my words if he stays cool. LLY-LLY

But most of all, and I only speak for myself: you have posted the same line, I'm guessing 500 times. "rogue heat source". Who is changing your energizers?

Sorry, I guess I am just worked up over the fat in this thread. But I have to say, I'm only voicing an opinion, that I mean no disrespect with.

I don't take any, its all good. I don't tout that poll as gospel, but it is damn enlightening. One guy voted in all three categories which the computer wasn't ready for, it threw the numbers off. No big deal. There is still viable data there, main point is this is not a problem for EVERY 04.5 and 05.

I haven't posted "rogue heat source" 500 times, but how else do YOU explain such widely different reports from different trucks? Like I said, they can't ALL be wrong about not overheating.

Since you wanna throw Rick at me, explain to me Rick's truck that was not overheating but was worked on and became an overheater. Rick didn't change. He knows his business. So explain to me how airflow causes that to happen.

The poll is useful in explaining that LLY's under load overheat. It is very simple for a reason, to eliminate all the fluff you keep trying to put into the million "scenarios" out there. The main focus of it was to prove that the trucks overheat when under load, the 10k figure was just chosen to ensure that the truck was at least having to work for a living even if it was on flat ground. Tell me how that isn't useful to know and has no value.

.

So TX. Tell me how to prove it is a bad head??

Bad castings in heads eventually show up as cracked heads and blown head gaskets from overheating just that head. They don't dump their heat into the coolant cause they can't (bad flow holes) and warp and/or crack.

Now a more restrictive head might slow the water down. Giving it more time to heat up in the engine. If so, the inlet and outlet water temps will tell the tell. Frequently, this can be overcome with a bigger, higher pressure water pump. Sometimes the restriction is too great. Something similar happened to the 6.5 when they upped the power. The end result was dual thermostats and better flowing engine coolant in the head and block.

One down side to aluminum heads is that they do transfer more BTUs to the coolant than cast.

But as I have said before: The problem is not that the engine is making BTUs, it is the inability of the system to get rid of them.

" the heat is coming from the engine" Really? Ya think? Isn't it time to open your mind. I think a year was enough time to lose this argument. I'd like to see you win it, but


Yes, the heat is coming FROM THE ENGINE not from THE STACK NOT COOLING PROPERLY. You are so stuck on beating the heat rather than eliminating it. Great that you have Fingers with an overheating truck that increased his airflow and runs cooler. SO WHAT. Plenty of other trucks out there are doing fine. NOT GETTING HOT, and they don't have any ghetto dam.


"airflow is more than enough" have you been living in a vacuum? Fingers one run disproved that. That one run with an air dam represented more progress on this issue than the 1800 posts before it.

AGAIN, the airflow is not enough because HIS TRUCK HAS A PROBLEM. Otherwise it WOULD BE ENOUGH as proven by owners who tow without issue.

.

So TX. Tell me how to prove it is a bad head??

Bad castings in heads eventually show up as cracked heads and blown head gaskets from overheating just that head. They don't dump their heat into the coolant cause they can't (bad flow holes) and warp and/or crack.

Now a more restrictive head might slow the water down. Giving it more time to heat up in the engine. If so, the inlet and outlet water temps will tell the tell. Frequently, this can be overcome with a bigger, higher pressure water pump. Sometimes the restriction is too great. Something similar happened to the 6.5 when they upped the power. The end result was dual thermostats and better flowing engine coolant in the head and block.

One down side to aluminum heads is that they do transfer more BTUs to the coolant than cast.

But as I have said before: The problem is not that the engine is making BTUs, it is the inability of the system to get rid of them.

So you are saying without doubt there is not an LLY that is stock that can come pull up your hill pulling the same load as you and NOT overheat?

Not trying to piss you off or anything but you being a victim doesn't make ALL the trucks victims. If you are saying that this is an issue for EVERY LLY out there then I don't know how to reconcile this with all the guys that tow heavy and swear their temp gauge doesn't budge.

.

I don't want to do the argument thing with you. I've seen what happens.. I'm not trying to discredit anyone, just some bones to chew on, dog.

I agree that bad castings in heads generally show up as cracked heads, this was very true in the past but we are talking iron heads. In this case restriction or an area that just isn't quite thick as it should be that is allowing the heat to quickly get to the coolant would more than likely be the culprit.

It's just too much that Rick's one truck was fine then had its turbo and heads replaced and all of a sudden was NOT fine.

We didn't have that info last year KB, its new.

Maybe Rick can chime in and relate his experience with that truck.

.

I don't want to do the argument thing with you. I've seen what happens.. I'm not trying to discredit anyone, just some bones to chew on, dog.

LOL, thats cool too.

I just want some reconciliation from you on trucks that tow fine without issue, and you haven't provided ANY at all even with repeated request.

.

I'll put this out there for ya all to chew on.

Any run of engines is going to vary in output. Both HP and heat. You will see as much as a 5% swing from one to another. We have all heard stories of so and so's car that ran exceptionally well while his buddies just wouldn't get up. I think the LLY and it's cooling system are just on that edge, maybe a little over. So, depending on the character of YOUR engine with all it's little nuances, you fall on the wrong or right side of this problem.

Being that close, I think we can overcome this.

Someone call CBR over for some ice for this thread, its gotten hot too.

.

page 119 of this thread, posted by Rick:

More food for thought. I recently had a new motor put in 1 of my 05's. Before then the truck had not overheated in its short 7500 mile life. The new motor, however has overheated every time out. Not to the point of setting off alarms, but 2 marks from the red. The fan is screaming at this point. Because of this I beleive that the problem is definately inside the engine. Not the fan or the boost at altitude. I am on my 7th Duramax and 4 of them have been LLY's. 2 of them overheated, and so far 2 have not. I say that because my newest 05 has not pulled a load yet. I am not a GM basher either. I own 4 Duramax's currently. I believe they are great trucks, but the bean counters need to OK the budget to fix this problem.
__________________


True what you said about differences, we timed a dozen Mustang GT's repeatedly way back when I worked at a furd dealer (another story) and my buddy bought the fastest one, the car reigned supreme on the street scene for a while.

Anyway, the "replaced motor" in Ricks case was actually the turbo and heads. All the rest stayed the same from before. Truck was good, those items replaced, truck goes bad. Too much coincidence for me. KB wasn't around when this came out, so he may not be taking it into account.

.

The replaced motor was a long block, and showed as re-manufactured. After they replaced that and 1 injector they found that the turbo had some crap in it. They then replaced the turbo and the actuator.

On a side note the motor has "calmed down" a little. It is not going over 235* now and is getting excellent mpg. I will load it heavy soon and monitor it. My 04.5 now has over 160,000 mile and is not getting over 240* now. Is it possible that we are so close to the ragged edge on overheating that just simply letting the motor "loosen up" with mileage helps!
I stated before that I thought is was a "cluster ****** of inefficiencies!" Can it be that simple?

On a side note the motor has "calmed down" a little. It is not going over 235* now and is getting excellent mpg.

Break-in heat reduction, sure.

Tx,

I stuck my head in here about 6 weeks ago, when this thread started showing activity again.

Then I made a number of POSTS (http://www.dieselplace.com/forum/showthread.php?t=14625&page=33&highlight=killerbee) that I believe helped shift the paradigm of this issue to one that had a cause, or at least a weakness to be exploited, 2 actually. IAT, and it's thermal feedback involvement, and stack airflow. I made some postulations based on unloaded hiway observations of the fan of a few people including myslef, as well as observing IAT, and how it's temp spiraled uncontrollably with known airflow deficiency.

It might help to see those PAGES (http://www.dieselplace.com/forum/showthread.php?t=14625&page=33&highlight=killerbee) again. I feel good that it had the effect that it did, and put a number of talented people on the job to "think tank" down this road.

It was then that I offered my explanation as to why, one truck might, while another might not. About HERE (http://www.dieselplace.com/forum/showthread.php?p=623316&highlight=rope#post623316). And I'm not saying that I can conclude today that we cracked the nut. That may be in the weeks ahead, as we test a pressure changing mod or 2, plus cold air, on Ricks trip.

The replaced motor was a long block, and showed as re-manufactured. After they replaced that and 1 injector they found that the turbo had some crap in it. They then replaced the turbo and the actuator.

On a side note the motor has "calmed down" a little. It is not going over 235* now and is getting excellent mpg. I will load it heavy soon and monitor it. My 04.5 now has over 160,000 mile and is not getting over 240* now. Is it possible that we are so close to the ragged edge on overheating that just simply letting the motor "loosen up" with mileage helps!
I stated before that I thought is was a "cluster ****** of inefficiencies!" Can it be that simple?

Rick: How was the truck before it blew up? I just want some proof that there are trucks that don't show any signs of the problem. If there isn't any then fine, they are all broken and it is a waste of time to figure out why. But while there are trucks (alleged lets say) that DO NOT show signs of getting hot at all in existence you just have to wonder why. There are just too many that say they stay right there at or under 210 and never budge. They aren't on the edge or tipsy or anything, they are like their LB7 bretheren the way GM intended them to be.

.

remember the front end and cooling system was designed in 98, a few HP ago, and reportedly never changed through the entire evolution (except for the obvious chevy look, but everything under the hood and behind the grill stayed the same).

I would love to see some pics of the 06.

Tx,

I stuck my head in here about 6 weeks ago, when this thread started showing activity again.

Then I made a number of POSTS (http://www.dieselplace.com/forum/showthread.php?t=14625&page=33&highlight=killerbee) that I believe helped shift the paradigm of this issue to one that had a cause, or at least a weakness to be exploited, 2 actually. IAT, and it's thermal feedback involvement, and stack airflow. I made some postulations based on unloaded hiway observations of the fan of a few people including myslef, as well as observing IAT, and how it's temp spiraled uncontrollably with known airflow deficiency.

It might help to see those PAGES (http://www.dieselplace.com/forum/showthread.php?t=14625&page=33&highlight=killerbee) again. I feel good that it had the effect that it did, and put a number of talented people on the job to "think tank" down this road.

It was then that I offered my explanation as to why, one truck might, while another might not. About HERE (http://www.dieselplace.com/forum/showthread.php?p=623316&highlight=rope#post623316). And I'm not saying that I can conclude today that we cracked the nut. That may be in the weeks ahead, as we test a pressure changing mod or 2, plus cold air, on Ricks trip.

I appreciate that and your efforts are tremedous here, nobody doubts that.

We were all about the hot air intake thing way back on page 57 or so last year, its been recognized as a problem and tested and helps but doesn't cure. GM knows too, it was discussed with powertrain via phone and email last year. Obviously they are onto it just looking at the 06.

Stack airflow was measured last year as well, and attempts were made to increase it. Flow was previously checked at the grill and stack face both with and without the fan. We only really focused on it for a month, you keep saying a year of this, but the thread went to sleep from november to march since nobody had issues during the nice cold winter months.

JJ actually more or less stumbled onto the air dam idea by removing the splash plate and creating a rudimentary air dam out of the crossmember.

It doesn't matter who came up with what or when. Two things remain the issue:

1) Identify the problem. We have still not been able to do that, but many elements have been eliminated.

2) Overcome the problem. Progress is being made in that respect recently, only with regards to the ghetto dam.

As a side note the main reason I got onto the radiator BTU calc is because if the load is actually much less then perhaps staged electric fans would do the job, I was thinking 4 of them with two set to come in like at 210 and the other two at say 215. The flow of this setup if 4000cfm and if enough would free up HP and eliminate the shroud for more engine compartment air flow.


Shields up.

.

KB the LB7's got by with only 10hp less but CONSIDERABLY less open grill, much more restricted flow than now.

Who knows, maybe a big open grill is not the right direction, maybe the smaller one creates more stack head pressure by focusing the flow through that smaller area where the big open one creates big lazy pockets and turbulence.

Put the magnahelic to work :)

.

Has anyone actually taken an overheating truck to the dealer and been told there is nothing that can be done? I have heard there is a new cal, and they should have a couple of simple things they can check to see if there is a problem. Leaks in the charged air system, obstruction in the air inlet box, turbo efficiency, etc. I think it makes more sense than suggesting someone sabotage thier engine and make GM pay for it. Just a thought.

Dude I feel ya, but the sabotage idea is a result of the inaction by GM. Its really no different than "run it til it melts down" idea, the intention in both is to force a fix.

Yes, many have been turned away without a fix and no recourse. You tell me what you do then.

.

ljd, only your 4th post but it is a zinger! First/foremost welcome to the DP.

Numerous guys have taken their overheating trucks in. Best to take the time to read the thread (sorry its so long) to get up to speed.

As for sabotaging the engine I'm hopeful TxC was just having a moment. lol JJ

My Blue 05's temp never moved before the engine change. Now it does. Same run same load.

I have read the threads, but I really have a problem with someone suggesting they sabotage a truck. Run it til it dies, if you are within manufacturing specs as far as weight and everything else, no chips, fine, then it is GM's fault. Sabotage isn't, they are not the same. Again, the folks who have problems, I know the dealers have more info, get the new cal, check the air induction box, check the turbo efficiency, check the fan clutch, check for charged air system leaks. These things will help. And 230 is not running hot, neither is 240 depending on the conditions.

What kind of idiot would jump in here? Uh JJ! ?????

OK to vent our frustrations, some theories are attacked, ego's stepped on, techie "duals", its all good. Sometimes it is during these exchanges that we stumble onto something we hadn't considered before.

I haven't see any polls conducted on the DP that weren't flawed in some manner. Why? Humans are involved. Good points all around, just too many variables to make any solid conclusions. But it should validate in GM's mind that their customers feel they have a serious problem and seek some resolution.

Don't expend too much energy rehashing the old stuff, plenty of new intel on our plates. Moving forward, not sideways or backwards, will get us where we need to go. JJ's out.

My Blue 05's temp never moved before the engine change. Now it does. Same run same load.

THAT'S what I am talking about.....way too many that say the temp never moves out there to say the issue is global.

I promise you, my truck is not on any edge of instability or anything like that, I beat on it and cheated it and everything I could and the damn thing just laughed and said "bring it on!"

The temp NEVER budged. You make me wanna drive up and tow Fingers load up the ballbuster.

.

engine to engine can be different. 230 is not hot, I' sorry, its not. Leading people to think is seems a bit of a disservice. I am not saying there are no issues out there, but this makes it hard to separate things out.

engine to engine can be different. 230 is not hot, I' sorry, its not. Leading people to think is seems a bit of a disservice. I am not saying there are no issues out there, but this makes it hard to separate things out.

Yeah so you and me pull the same hill same trailer same day at the same time, on a 103* day and my trucks purrs along stays 205* the whole way, but your temp takes off and gets to 230* but lucky for you, we run out of hill.

When the next hill is two miles longer and I stay at 205* and my a/c is blowing nice and cold and you hit 250* and your a/c shuts off and bells and whistles and alarms go off and your truck loses power and you slow to a crawl with a mile still to go and the inside of your truck gets hotter than the 103* outside while I sail away in front of you without issue.....

I want you to then turn to your wife and baby and say "there isn't anything wrong with this truck."

.

engine to engine can be different. 230 is not hot, I' sorry, its not. Leading people to think is seems a bit of a disservice. I am not saying there are no issues out there, but this makes it hard to separate things out.
If you say 230* is not hot, try pulling the "grapevine" (I-5 South) near Bakersfield, CA with your 10k lbs 5er (much less weight than GM advertises), on a 95* day, with your totally stock truck , with your family aboard, at 35 - 45 mph having to be at WOT just to maintain speed and the temp gauge goes into the red and the DIC says "ENGINE COOLANT HOT", surrounded by Semi trucks and no where to go or get off the road, wife & children frightened to death, a/c off to keep from blowing up engine, and then you can tell me there is no problem!

In spite of all the people that say they have never had a problem, you have just not met the “right” or extreme conditions we have here on the west coast, while towing a large frontage 10k lbs plus trailer with OAT's exceeding 90* with higher altitude, with a steep 5 to 6 percent grade.

I’m sure there are similar conditions exist elsewhere in this country.

circles. O O O O O O O

BS Tx. You just like to argue. Composes half this thread.

I AM putting the magnehelic to work, that's why I'm not occupying as much hard disk space.

700 posts, all about the cooling system, all defending the same undemonstrated position. And yet your truck has no problems. What the gig?

Any time an engine is hotter than the full open setting of it's thermostats, it is hot. The cooling system is maxed out. Overheating is when temp rise goes unchecked. Usually ending in a coolant puke.

If you are running at a steady state 230* then you are Hot, but I wouldn't say overheating. You are painfully close though.

circles. O O O O O O O

BS Tx. You just like to argue. Composes half this thread.

I AM putting the magnehelic to work, that's why I'm not occupying as much hard disk space.

700 posts, all about the cooling system, all defending the same undemonstrated position. And yet your truck has no problems. What the gig?

I guess you can't say that about my experience. The example I depicted is not a hypothetical one.

circles. O O O O O O O

BS Tx. You just like to argue. Composes half this thread.

I AM putting the magnehelic to work, that's why I'm not occupying as much hard disk space.

700 posts, all about the cooling system, all defending the same undemonstrated position. And yet your truck has no problems. What the gig?

I don't have come demonstrate it, people do all the time. Since I have the truck with the temp that doesn't move I could just as easily say keep your GMC POS out of the way.

Lay cash down we will see if all these trucks overheat or not.

.

engine to engine can be different. 230 is not hot, I' sorry, its not. Leading people to think is seems a bit of a disservice. I am not saying there are no issues out there, but this makes it hard to separate things out.

To YOU 230 may not be hot- to me it is. I call it to hot when the same load , same day with my 01 lb7 won't hit 210 and the 05 will hit 235 and I need to back out. Oh yea- the 01 was able to do 70+ up the hill the 05 was struggling to make 55. I have taken my truck in several times and asked the dealer to check for whats causing me to run hot, first 2x there was no flash, 3rd time they had a flash, basicly adding some functions to the DIC and topped boost at 22 psi not the 27/28 I was seeing. My perspective is of 5 personal Dmaxs and having 2 employees with them on my recamendation, both our 05's run hotter, the 2500hd is a delivery /sales truck, never tows more than my brothers boat, but stiil run 210/215 24/7/365, but gets 2mpg less than the 02 we moved in the fleet, GM - EPA who ever, what ever, it needs to be fixed. I just want my truck to do the same work the other ones I have can do.
:rant:

Tx, Counseling would be a better use of the money. But I'm not opposed to a wager.

I don't have come demonstrate it, people do all the time. Since I have the truck with the temp that doesn't move I could just as easily say keep your GMC POS out of the way.

Lay cash down we will see if all these trucks overheat or not.

.

If you have a gooseneck hitch and airbags, Man have I got the hill for you! :)

Just for the record, Part # 10386198, is the correct lower deflector. Mine is on for me next trip to Denver. I will post if it does any good.

engine to engine can be different. 230 is not hot, I' sorry, its not. Leading people to think is seems a bit of a disservice. I am not saying there are no issues out there, but this makes it hard to separate things out.
To You 230 is not, to ME it is. Same day, same load, 01 vs 05, 01 210 ect, 70 mph- 05 235ect 55 mph and I backed out. YOU tell me, no problem, I beg to differ. Truck has ben flashed, delar has changed the fan, what, I should tell the Wife and Kids, sorry no A/C in this , my 50K truck. I don't think so.:rant:
On edit- Ok Maybe I'm a little STEAMED about my truck. Sorry.

Fingers: If you are running at a steady state 230* then you are Hot, but I wouldn't say overheating. You are painfully close though.

That's as good a way of explaining it as I've seen here on the DP. JJ

How much?

OK, howz about everyone close your eyes for a second and take a deep breath! Everyone had their testosterone fix for the day? Geesh, when we go on a tear, yeeeehaaaaaaaaa! Actually these posts have been a little milder than some of our previous rounds. lol

Fact is TxC's truck might just handle that hill, there is no hard proof that it won't. Wagering money on something that has so many intangibles and variables as this isn't a solid bet for any of you. Nor will it prove anything that we don't already know! So save your money! How about overheating solutions!

The frustration is understandable. Obviously folks are taking ownership of their positions, this is normal. Let's find a better way to disagree or present our questions when testing each others theories or hunches. If any of us were that much smarter than the other we would have solved this a long time ago. Humbling!

Don't make me take out a can of 'woopass'! lol Seriously, let's get back to constructive suggestions. JJ

For me it was load induced. Same road, same ambient, same week, - one with no load temp did not budge, with load ( 4k camper ) temp kept climbing and would not stop till I backed off.

All I am saying is that RDL had one that did his work and the temp on it never moved until parts were swapped, 60% owners in the BS poll report the same, so it ain't 100% of the trucks.

You think we have a stink at roughly 40%????? imagine 100% overheating.

.

By the way, BS stands for Basic Stuff.

:)

.

I'm not at all hot about this topic. I stand behind my observations. My belief is that, all other things being equal the tendency of a given vehicle to OH, is inversely correlated to the inherent flow differences (delta P) across the stack. Lets just call that KB's correlary A. Show me a truck with .3 iw dp, no fan, I'll show you an overheat today on I-17 with a 16K hi-drag load.

If there is a valid test we can run to prove/disprove the KB-Correlary A, my wife will let me lose nothing on this. So I just won't tell her. I'm good for $$$. I don't mind less, or nothing, my ego isn't riding on this. The only thing I would ask is that the money would be used to further this effort, recycled to help Fingers or whomever can use it to run mod trials.

Back to work: Tx, can you get your hands on a 1" or 2" magnehelic, and run your stack numbers over the speed range 25-70 mph? easy, easy to do. Don't need a load. Collect a few Houston posters numbers as well. We'll get a database going.

BTW, any of the phoenix guys are welcome to come over and do the same, it might be good to get a x-section reading on these vehicles.

Is there no nice big hill somewhere in the center of the U.S. where the different partys could meet with the trucks, trailers...and tow the s**t out of it?
That WOULD finally prove the overheating theory for good! Needed would be only a truck that for sure overheats and one what for sure (who knows...) never overheats...all LLYs of course. Wouldn't that be fun too (have some beers afterwards...)? :exactly:

to cadent45 , it does sound like there is a real issue there. The a/c system does have a service fix though, and there are other things the dealership can check, and some things you could too. Just trying to help, have you checked you air intake to make sure the rubber patch didn't come off the fender and het stuck in the box? Check the fluid level in the trans, too much can make 'em run hot. Dealership could check the turbo efficiency and check for charged air system leaks. Just some thoughts.

to cadent45 , it does sound like there is a real issue there. The a/c system does have a service fix though, and there are other things the dealership can check, and some things you could too. Just trying to help, have you checked you air intake to make sure the rubber patch didn't come off the fender and het stuck in the box? Check the fluid level in the trans, too much can make 'em run hot. Dealership could check the turbo efficiency and check for charged air system leaks. Just some thoughts.

I think you have mentioned this check for "turbo efficiency" twice now. Explain to me how thats done, kinda curious how one would go about running that test.

.

This may be what he is talking about:

A Vane Position Control Solenoid valve (located on right side of turbo center-section) uses engine oil pressure and computer controlled valving to move the turbo's variable vane mechanism. The analog sensor reads the vane position, then an inline 10-bit A/D signal converter converts the analog signal to a digital component that is read by the ECM. Both the sensor and the control valve are easily serviced/replaced, and new OBD II diagnostic procedures allow the technician to monitor the operation of these components.

I got this off an article from the Diesel Page site regarding the LLY. JJ

This may be what he is talking about:

A Vane Position Control Solenoid valve (located on right side of turbo center-section) uses engine oil pressure and computer controlled valving to move the turbo's variable vane mechanism. The analog sensor reads the vane position, then an inline 10-bit A/D signal converter converts the analog signal to a digital component that is read by the ECM. Both the sensor and the control valve are easily serviced/replaced, and new OBD II diagnostic procedures allow the technician to monitor the operation of these components.

I got this off an article from the Diesel Page site regarding the LLY. JJ

Thats more turbo function (other than rotation of the vanes, this is measured as boost pressure).
Efficiency can only be calculated if the airflow into the turbo inlet and boost pressure at a given rpm is known...

http://i17.photobucket.com/albums/b82/socal-lly/100_1699.jpg http://i17.photobucket.com/albums/b82/socal-lly/100_1693.jpg I am done with this truck I hope you guys get your trucks fixed.I put mine up for sale while waiting out the buy back process

socally, you can only have patience for so long and put up with so much. Certainly hope your experience is better with whichever brand you end up with.

I see Fingers is back from his runs. Spill the beans brother! JJ

Thank you JJ I wish the best to all you.It was the last time for me it was 113 degree out side the heater was on 90 and the thing would not go over 45mphsocally, you can only have patience for so long and put up with so much. Certainly hope your experience is better with whichever brand you end up with.

I see Fingers is back from his runs. Spill the beans brother! JJ

That's a shame socal. You have a lot of work in that truck. What's next?

No Joy for the Ghetto Air Dam. But I like the way it looks, so I am going to keep it on anyway.

If I can cook mine when it is 80* outside, there is no hope when it is 120*.

I noticed you have a buckstop front bumper on your signature. Does it look like the one below. Notice how you lose the spoiler and the bumper rides much higher than the stocker - this makes you create air pressure on the bottom of the motor - dramatically cutting airflow through the engine compartment. It also decreases the air pressure into your radiator (the stack). Raising the truck makes it worse. Maybe one of fingers air-dams would help you a great deal. You need a front spoiler of some sort or you are toast.

Also, if I had a steel bumper like that, I would increase the size of the air passages through the bumper to increase air pressure on the bottom front of the radiator. Cutting up my stock chrome bumper would get kinda messy if I tried this on mine...


Awwwww hell here we go again ......:eek:

.

Awwwww hell here we go again ......:eek:

.thank you

I deleted my post. I am gone. Don't worry, I won't be back...

- jeff

That's a shame socal. You have a lot of work in that truck. What's next?I think I might buy a F-350 or a old cummins for towing and a sportscar

I deleted my post. I am gone. Don't worry, I won't be back...

- jeff

Praise Jesus! ):h

I deleted my post. I am gone. Don't worry, I won't be back...

- jeff

Well now Txopher, you must be well satisfied with your performance.

ed

I deleted my post. I am gone. Don't worry, I won't be back...

- jeff

Its not you guy, or the idea, the idea is great, but its been so re-hashed and bashed on by his dealer that its like stepping on a mine. This is why people always keep saying that even though the thread is long and will take a long time to read, to please go back and read what has been covered.

When you are the 50th guy to lay blame on the bumper it gets old, especially for the guy with the bumper, after the bumper has proven to not be an issue.

I said what I said to save him the rant, cause when I saw your post I could hear his head explode clear to Texas.

It wasn't anything on you at all, so don't be run off. That idea is a no go but your next one could be key.

.

Well now Txopher, you must be well satisfied with your performance.

ed

It wasn't a performance at all, after you see my post you will understand. I just had more to type than you.

.

the idea of a towoff would be great, invite gm and the media,I dont believe gm would be very thrilled with the results.txc do you think the powertrain or other gm contacts would be interested in seeing this first hand? just a thought,would be cheeper than legal fees

Its not you guy, or the idea, the idea is great, but its been so re-hashed and bashed on by his dealer that its like stepping on a mine. This is why people always keep saying that even though the thread is long and will take a long time to read, to please go back and read what has been covered.

When you are the 50th guy to lay blame on the bumper it gets old, especially for the guy with the bumper, after the bumper has proven to not be an issue.

I said what I said to save him the rant, cause when I saw your post I could hear his head explode clear to Texas.

It wasn't anything on you at all, so don't be run off. That idea is a no go but your next one could be key.

.

Thanks Chris.

the idea of a towoff would be great, invite gm and the media,I dont believe gm would be very thrilled with the results.txc do you think the powertrain or other gm contacts would be interested in seeing this first hand? just a thought,would be cheeper than legal fees

It seems to me that while they are willing to talk about it, and are interested in our ideas and such, not a one is willing to commit to jack. This becomes obvious quickly talking to them. You understand the huge liability here.

You wanna make a scene get 20 trucks together and meet up with Car and Driver and show them the deal. They seem to LOVE to bash the General, it is very obvious in the articles they write.

It is on my list of things to do to call that GM lady tomorrow morning.

.

Now that you brought up GM, I see she was here on the 18th, the day she signed up, as well as the 19th. I think she said she had an engineering meeting that tuesday, hopefully she was showing them this site and the scope of the issue.

.

Tx, if you can, find out if the 06 fan is an EV "smart" design or something else.

I need to test drive one I guess.

A couple of weeks ago I posted that I had heard from my local dealer and that they had a fix for the overheating. I dropped my truck off for the day. They called me later in the afternoon and said that they thought that my gauge may have been recieving faulty info but that was not the case. They also tryed to reflash but it had already been done. Note that this is the third time that I had brough it in, although all three times were to different dealers. He told me that a couple of GM engineers had been there and thought that they had fixed a few be recaling the gauge. He gave me the 800 number and said sorry, call them. He also said that they have put you in a database of overheating trucks.

I was headed from Phoenix to Yosemite and then to South Lake Tahoe so I decided to run Rotella syn for extra temp protection. Note that I am towing a 33' fifth wheel waying approx 12k. Well the maximum temp that I got to on that trip was 240+/- but my ally also got that hot. This was also trying to keep the rpm's under 2800 on steep uphill grades.

On my way to Yosemite I took it real easy. Engine temp never got above 220 and Allison the same. From yosemite I want up hwy 49 which is rather slow and no serious grades to speak of. Once I got on hwy 88 from Jackson to Lake tahoe I began to push it a bit. I ran all the way up to approximatly 8000 feet (over Donner Pass I believe) and never saw the engine go above 220 and the transmission the same. note that OAT is ~80. I am beginning to think that the dealer did something and did not tell me.

On the way home I ran the lower portion of the "Grapevine" going south at 42MPH in third with the rpms at 2500 in third gear. Set CC. Max temp was 235. Allison at 220. OAT ~90. For those that don't know I think the First section of the grade is about 6% for 6 miles. Not to bad. Once the first section leveled off I brought it into fourth gear and same RPM's. I think it was 55 mph for the rest of the hill hitting 60-65 on occasion. Engine temp went to 240+/- Allison up to 240. OAT~80. Getting worried. Once I topped the grade it all came back down to normal. The last grade I hit that I thought was somewhat substancial was from Blythe to Quartzite. This hill is normally not all that bad but the OAT was 118. I held the tranny in 4th again and ran 55. The engine was only at 220 now but the Allison was at 240 again.

The thing that is really confusing is that I have never, to this point, had any problems with the Allison getting that hot. When I have got uo to 250+/- on coolant temp the allison would maybe make 220-230 but never close to the 3/4 mark. I know that before as the engine got hot, so did the allison. Based on the allison temp my engine should have reached 260 easy. Is it possible to adjust the gauge to read lower than it should?? Anyhow I have not called the 800 number because I am supposedly on some overheating database. The service adviser told me that the people that he has delt with on the same problem have been taken care of by GM. He didn't say how.

I hope they get a fix soon. I really want to put some mods but I am not touching it until they fix the existing problem.

On edit: the truck would hit 235 somewhat often on hills, then the fan would come on and cool it.

I am through too. My dealer is buying mine back too. Plus if I want a deal on a 2006 in 2 weeks, when they get some in. I tired of being up tight pulling my fith wheel. Maybe 06 will be better. See ya.

You don't want to hear it but yes, they are actually lowering the gauge readings and slightly raising the DIC warnings.

Thats what I would call a real solution.

These are the fixes I have heard from GM so far, plus one about thermostats being off a couple degrees.

.

Is there a thermostat that maintains a lower operating temperature (180*)? If so, would that help by maintaining a lower starting temperature point?

All my band-aids seem to be helping. My latest trip with a horse trailer on flatbed to Colorado w/S&B bottom & side feed,no plastic plate,
air bags, Predator Tow Tune, OEM air dam
catless, egr blocked, 1/2 turn down on frontend

mt @ 75mph the motor cooler than I have ever seen.
194* ect & its 97* oat

loaded 104* oat 228* ect was the hotest. I can live with that if I have to. Now for my version of a ram air and some louvers in my hood!!

can you guestimate what part of the improvement is represented by the dam?

Are you hearing the fan less mt?

AC improvement?

I believe it is making the fan work more as it should. It added to the effect of removing the plastc plate. I never hear my fan mt. I am towing my wifes truck right now in 102* oat and no fan! Now that you mention it ac is working very well today.

uh huh! awesome!

A few recent developments on sealing up the stack could make it even better, go look.

Rick, how heavy are you on this run? Are you into any mountain climbs or long grades? This truck isn't stock like the last one, correct? Just making sure we're comparing apples to apples! The mods to the front end appear to be getting flow across the stack. KB and others are nailing this thing pretty good on the solutions thread. Ol JJ's helping em out! lol They'll get er' done in spite of my help, don't worry. JJ

JJ, 20k gross going to Denver. Thats a good long gradual climb with a gooseneck stock trailer on top of a flatbed. Today I'm 16k heading back towing my Blue 05.

I had tested this base combination before, but for this trip I went kitty less and added the extension and blocked the EGR. EGT's never went over 1450. Stock I saw that.

All my band-aids seem to be helping. My latest trip with a horse trailer on flatbed to Colorado w/S&B bottom & side feed,no plastic plate,
air bags, Predator Tow Tune, OEM air dam
catless, egr blocked, 1/2 turn down on frontend

mt @ 75mph the motor cooler than I have ever seen.
194* ect & its 97* oat

loaded 104* oat 228* ect was the hotest. I can live with that if I have to. Now for my version of a ram air and some louvers in my hood!!

You talking torsion bars? If so I been wanting that tried, nose up just can't be good.

.

You talking torsion bars? If so I been wanting that tried, nose up just can't be good.

.
Yes.
Coming home from Colorado pulling the Blue 05 the ECT never moved on the gauge. When I got to a big hill the fan kicked up a gear and the gauge still never moved. I would say we have definate improvement. I will do JJ's full on frontal seal tomorrow!

Yes.
Coming home from Colorado pulling the Blue 05 the ECT never moved on the gauge. When I got to a big hill the fan kicked up a gear and the gauge still never moved. I would say we have definate improvement. I will do JJ's full on frontal seal tomorrow!

Sounds good. I didn't know you had the EGR open. Did you always have the airbags before or did you add them to help with the nose up problem?

I am sure you thought I was wacked when I brought up the torsion bar thing, but it is a good move to get the right stance. Your truck was just way too nose up/tail down in the pic you posted. Air bags or helper springs along with tweaking the bars up front should get the stance we want here for proper flow.

.

I blocked the EGR for this run, and removed the cat. I had the air bags from the start, I had just not had time to put them on. The fan acted like you would think, cycling on and off with load. I don't think its enough yet, but we are helping.

Rick,

Did you have time to seal up the front end before this run? JJ :)

RDL, PM me. I have something that might help. I will not be monitoring this thread any more.

Rick,

Did you have time to seal up the front end before this run? JJ :)

I will perform the JJ " full frontal seal " tomorrow at 9:57 am CST.):h

Did we run Fingers off with all the bashing?Censored

Sadly so! :o: Just when we're making serious progress things got totally out of hand. I don't hold out much hope things will resolve. :( Maybe the guys that were getting it done will continue to work the issue on the side without all the interference and BS. This DP day has turned to crap! JJ :o:

I blocked the EGR for this run, and removed the cat. I had the air bags from the start, I had just not had time to put them on. The fan acted like you would think, cycling on and off with load. I don't think its enough yet, but we are helping.

Do you think that when you were so far nose up that there was enough air being blown underneath and forced into the engine bay as to affect the temperature at the fan face? With the high pressure blasting underneat stack flow would also be reduced. The fan may flow a lot but I would think a 70mph airstream the size of the vehicle would outdo it. Maybe cit can do some calcs on that or modeling, truck nose up at 65-70 mph.

I think the splash plate was smoothing the flow as it blasted under the truck, helping it arrive much more forcefully. Without the plate the air slams into the crossmember and is disrupted. Air doesn't pay much attention to angles until they exceed 30 degrees, but the crossmember is near vertical so the air had no choice but to take notice. Fingers dam does much the same thing but is properly placed further ahead to take advantage of eddy current drop behind it.

.

I hope Fingers at least looks in and contributes to this thread, all that bickering wasn't an issue here :(

.

Catch you guys later.

Good luck with the problems with your trucks.

.

TxC, that last post sounded too much like a farewell to ol JJ, that is not in any of our interests IMHO. You are still the lead for us with the GM folks. Nothing that transpired over this weekend changed that fact in my mind. ;)

Things were said, things got hot, opinions were exchanged, flamethrowers used a couple of times, hell we do that from time to time here on the DP. ;) Let's sleep on this and regroup tomorrow. JJ :)

Please, if all those that have a OH complaint, take a look at a new poll

HERE (http://www.dieselplace.com/forum/showthread.php?t=38875)

Thanks a ton gang. Great BB here. I'll sure be testing but with a minor load compared to most. But the grade and length of hill is quite substantial up the Continental Divide. I'll post results end of July.. and hope they're good.

Happy to report a flawless trip. Bone stock. Temps at rock-steady 210*, trans at 170-190/200 max. Considerable noise from the fan clutch (that's a good thing) with the AC on and up grades but nearly none with it off just to test. Hope the rest of you can get the issues resolved.

Nictane install coming up along with the oil drain valve and probably a cat-back. May go for the Edge/Attitude as soon as I can clarify warranty. Got my first oil change at the dealer in Butte free of charge. They also changed the Allison spin-on filter at 1800 miles. Shoulda seen the service writer's face when I told him I didn't have a DIC (to reset for oil interval). Also he tried to tell me there are only 2 zerk fitting on the front end. He now knows there are 11. Thanks gang.

Just got a call from my dealers service dept. he said there is a new PCM or ECM update that he claims is so new that they can't even download it yet to their Tech 2. I asked about the 'other' update and he said this has been the only one?



He also said there is a possible fix by replacing both t-stats. Apparently there is no way to test them and if one sticks you will only overheat while towing. he is going to do this install on a different LLY and get back to me.

OK, I can't believe I'm gonna say this. If you guys can get a vendor to donate an electric water temperature gauge and 2 senders I will make adapters and put them in my radiator hoses.
I will not at this point un-due what I have done, nor will I stop doing modifications I think will help. But at least we will have a starting point and I will make a second set of adapters to install in another truck if needed.


I also vote we get all this stuff back on this thread. It is too time consuming surfing 4 different threads. I would like everybody to feel free to post, just check the testosterone at the door.

If we can come up with double the stuff I will do the same to my LB7.

KB, I'm over here.

What is cac? The probes on my thermometers are 1/8 x 6". Everybody questioned the results when I taped them to the hoses. Is taping them to metal that much better?

Rick, it just may be the original overheating is just too long and unmanageable anymore. 200+ pages is a bit much to expect folks to sift through! :o: We're hearing a lot of the same questions we heard several months back. :( Maybe it would be best to capture the major points out of the original thread and either tack them onto the "OS" thread or just start with a new one. Other thoughts? :confused:

Still think those that are working this moreso from an engineering and technical perspective should continue to have their "conferencing thread" available to them. I like that term better than "Private Thread", I might just change that to be more politically correct. ;) While I expected it would step on a few toes, the last thing I intended was to offend anyone. Just trying to get er' done. :D

Are you on the road? Curious to see what sealing up the front end and stack did for IAT's , ECT's and fan action. JJ :)

Just a thought here but maybe something like SD's intake manifold could be used in line with the rad hoses then you could just screw the temp probes in the actual coolant flow. I would do this but I don't have access to my LLY for several weeks

KB, I'm over here.

What is cac? The probes on my thermometers are 1/8 x 6". Everybody questioned the results when I taped them to the hoses. Is taping them to metal that much better?

CAC= charge air cooler

Those probes really are not suitable. They are really good for putting in between stack members and such, but too big for this.

When you put a sensor on rubber hose, you have a 5-10 degree temp drop to the sensor, maybe more. It has insulative properties, moreso than metal. Aluminum might be only 1-2 degrees. That's where the question was. Obviously best to measure the stream, but a close second, is a quick reacting sensor on the metal. Looks like the rad has plastic in/out. May have to settle for that as a practical compromise. Insulate as you did, we do the best we can.

The idea is to build a correlation between temp drop (rad and CAC), and airflow. Also see what happens with those drops as ECT climbs. IAT also.

Don't you have a steep run near you?

You can decide which thread you want to run your tests, I have no pride.

what was the company you used for the temp sensors?

charge air cooler?

http://www.ProfessionalEquipment.com
2 x T100-4039 Traceable Mini Thermometer with NIST Certificate @ $34.95 each = $69.90

As many of you know I currently have 3 over heaters. One of them is over a year old. Gm gave me a customer loyalty check on that one and promised to fix it "when they knew how". I recently took both my 05,s in for overheating. I presented the mechanic at the dealer with all my research and with the web address to this site. He called (who ever it is he calls) and sent them the info. At this point I assumed we were done.

This morning I got a call from the mechanic. He talked to a GM engineer this morning and was told a fix was close. More BS I assumed! Then he started asking about my monitoring device, specifically would it read "calculated fuel rate"? I checked and it does. They have asked me to monitor that for them.

A couple of things popped into my head;
Could this be a genuine attempt to find a fix?
Could this be a way to monitor modifications and ultimately blame them?
Could this be an attempt to just buy more time?

I guess I need some input from you guys on this possible "double-edged sword". I don't want to inadvertently ruin an attempt at a fix, but if I can help I should. Bear in mind I gave them all my data and this sites address, so they should know what mods I have done and how they have helped.

I am leaning towards helping them, and being completely honest about my modifications. If my Predator helps keep my truck from overheating, GM needs to find out why.

I have my e-mail address in my signature. Anybody that does not want their reply viewed by others can e-mail me direct.

Sure would be nice if there was a actual fix, not a band aide. Go get'em Rick!

Intercooler, technically it is used between stages of compression. We have one stage only, normally called CAC instead.

Like you say, sounds like you gave them this thread, then they know what you have done. If they wanted to hurt you, they already have it. They know you are a customer down the road, i'd guess they are sincere. just a thought

They are stalling...they have the fix. The attorneys are in damage control now.

I'd say go for it. Might help them get it right this time.

Rick, if you don't mind having to do the logging, just get low mass thermocouples for the gauges you have.

Anyone find a 4 station data logger? Does THIS (http://www.professionalequipment.com/xq/ASP/ProductID.2494/id.22/subID.176/qx/default.htm#) log?

Looks like it does log. That would make your life easier. I could use it also.

kb, I don't think they are interchangable?

Anyone working in HVAC may have access to something like this http://us.fluke.com/usen/products/2620T.htm?catalog_name=FlukeUnitedStates&Category=THETOP(FlukeProducts)

We use small handheld fluke thermocouples at work for temp corrections on pressure tests. They are only single channel with no data aquisition.

As many of you know I currently have 3 over heaters. One of them is over a year old. Gm gave me a customer loyalty check on that one and promised to fix it "when they knew how". I recently took both my 05,s in for overheating. I presented the mechanic at the dealer with all my research and with the web address to this site. He called (who ever it is he calls) and sent them the info. At this point I assumed we were done.

This morning I got a call from the mechanic. He talked to a GM engineer this morning and was told a fix was close. More BS I assumed! Then he started asking about my monitoring device, specifically would it read "calculated fuel rate"? I checked and it does. They have asked me to monitor that for them.

That's good, real world observations, IMO.

A couple of things popped into my head;
Could this be a genuine attempt to find a fix?

I believe Yes. GM is Not blind, slow, Yes.

Could this be a way to monitor modifications and ultimately blame them?
Could this be an attempt to just buy more time?

I guess I need some input from you guys on this possible "double-edged sword". I don't want to inadvertently ruin an attempt at a fix, but if I can help I should. Bear in mind I gave them all my data and this sites address, so they should know what mods I have done and how they have helped.

GM already had this Site address ( TxC, not bad), maybe not the same Group. GM has many Groups, as more Groups come online with this issue the focus refines and the closer to resolution.

Providing them with data is a None Issue, IMO. You have posted most of it on this Forum.

I am leaning towards helping them, and being completely honest about my modifications. If my Predator helps keep my truck from overheating, GM needs to find out why.

Go for it Rick, I believe it is a positive effort, Agreed.

I have my e-mail address in my signature. Anybody that does not want their reply viewed by others can e-mail me direct.

What has been done in the Past is OBE.

Forward with best effort is positive for everyone.

FWIW.

Idahofox

They are stalling...they have the fix. The attorneys are in damage control now.


Unfortunately I am starting to believe that this is the case. The 06 model not only proves they know there is a problem but they have the fix.
So now it comes down what is the most cost effective way to make us go away. :shake:

Unfortunately I am starting to believe that this is the case. The 06 model not only proves they know there is a problem but they have the fix.
So now it comes down what is the most cost effective way to make us go away. :shake:

How many Know what the '06 Will/Will Not do?

Idahofox

Rick,
First off thank you for all that you have done! You have helped all of us with overheaters. I think GM honestly wants your data for a fix for all overheaters. As has already been said, if they wanted to do you harm they already have the means to do so. I think they want/NEED your data cause it's real world and not some wind tunnel. Thanks again.

I see the problem now Rick. How about that logger, maybe we can get up a collection

How many Know what the '06 Will/Will Not do?

Idahofox

True, excellant point.
Pure speculation on my part, but I can't imagine all these little nip tucks are purely cosmetic.:cool:

from Blizzardplowman
""I was talking to a manufactue today and was given this info on the 06 Dmax changes:
Boost increased to 30 psi
Increased coolant flow
Larger radiator
Modified fan shroud
Coolant fan has ring around outer edge of blades and is now ECM controlled by an electro-viscous clutch. (Trailblazers use this strategy)
Increased size external trans cooler
Larger lower radiator hose
Quick connect lower radiator hose and intercooler hose connections
Larger EGR cooler
Intake air heater used on both trucks and vans (different than on on LB7)
Second Intake air temp sensor to monitor IAH and also for fuel timing strategy based on actual air temp going in engine
Many added and/or enhanced DTC's
Maximum fuel rail pressure increased to 26,000 psi
High pressure relief valve relocated to left fuel rail
High pressure relief valve will not completely close once it has opened and will require an engine restart to resume full pressure again.
Elimination of the fuel cooler and FICM
FICM functions are built in to the Bosch ECM
Faster 32 bit ECM will support up to 5 injection pulses per combustion event
LB7 injectors operated with 92 volts, current LLY's are 48 volts, the new LLY will be 24 volts, thus the reason fuel cooling is no longer needed, as the resulting amperage is less.
New glow plug controller (GPCM)
ECM GPCM and TCM are CAN protocol
All injectors are flow tested and laser etched with this data. A bar code reader tracks this data as the engine is built. Each injectors location in each engine is then entered into a database. ""

smd, I remember somthing just like that concerning the injectors when the lly came out. I don't know if its pr or what, but I don't trust the 06 yet either.

No, I was offering my help, ideas and resources, but was getting smashed, bashed, abused and kicked to the curb for what???? So the same path would be followed anyway.

Seems it's a dumba$$ idea if it comes from outside the chosen ones, they all band up and attack it, right up until the chosen ones crap doesn't work then all of a sudden geeeeeee lets try this, glad we thought of it.

You tossed the collective power of the DP aside for that. Seems to have pissed off a great many to please a few. Good move.

Kinda wish I never laid out that stuff about measuring multi point into my laptop, its entertaining watching the airflow design thing go like wild.


edited for content...

TxC,

The "overheating team" is taking more of an engineering/technical approach to this problem, so they need hard data. While we talked about numerous ways of "finding a fix" on the original overheating thread we weren't getting it done. These guys have taken the ball and are moving forward, testing different theories, comparing technical aspects and viewpoints, and constructively working together to solve this problem. Others like myself are doing whatever field testing we can to assist them. This is the first time we've had a concerted effort with some direction from the DP members.

While we could use your help, and I wish you would, I certainly understand any hesitance on the teams part to invite you into their discussions given the tone of your recent posts.

Shields down! Nobody has attacked or demeaned your technical input or , it was only when the personal attacks started that a lot of a$$es were shown. Everyone else seems to have recovered from last weekends fiasco and back on track, that is everyone but you. Eventually it may turn out that you are right, I would be thrilled! I for one don't care who gets it right, just nail this on the head so we can put it to rest and enjoy our trucks!

I can't PM you from work, I started to wait until this evening to post a reply to you personally. But IMHO this needs to be said publicly. I'm certain everyone welcomes your technical input and intel on this issue, but the sarcastic comments and jabs will only serve to drive members further away from your posts.

You and I go back quite a ways on this issue, I really want you at the finish line when this race is over. If it is a matter of pride, then I'll take the hit and admit I was arrogant, stupid, whatever it takes to get the right people on this. If an apology is needed, I'm sorry!

No flame, just straight talk! It's not too late for all of us to mend this fence and move forward! JJ

"You tossed the collective power of the DP aside for that. Seems to have pissed off a great many to please a few. Good move."

I humbly disagree with that statement, I have never seen the DP members more focused on this issue and working together. No posts about mine does/yours doesn't, no rehashing the same stuff we did 6-7 months ago, so far it appears to be working. I didn't start that "Conference Thread" to isolate any of the DP members from this issue, it is likely the most watched issue on the DP right now! The team could have snubbed it, continued with business as usual hashing/rehashing the same sh_t, different day, but they haven't. Read the conferencing thread, I've never seen this kind of analysis being applied to this problem. Your statement is not supported by the facts!

That being said, I am personally asking that you bring your technical talents to bear and assist us with solving this problem. You are still our link to the GM powertrain folks, we need your input and support. However, I will not open the door to the Conference Thread, that must be done by a member of the team. Right now that is unlikely, you are in the drivers seat on this.

Give this some thought. There is absolutely no bad feelings on my part towards anyone over the events of this past week. Surprisingly the overwhelming majority of PM's have been very supportive, thanks to all. Enough said, we have work to do, you coming? Hope to see you working with us, not against us! JJ

It was the trashing of my technical ideas and info that started that, maybe you should read back. I will say again, just to be clear for the 400th time, the ONLY fix will be to identify the problem and correct it. These band aids and stuff are great to reduce the issue but are not the SOLUTION.

If you think you can go back and find where I stood differently then have fun looking, blow your time however you like. If you can find where I did other than RESPOND to someone first trashing me do that as well, same thing applies for what turns you on.

There has been some very good stuff come out, mostly from Fingers, alot is still rehashing the same old in detail, but a decent effort overall. With some good measurements maybe something will finally be learned.

My help isn't out of the question if it becomes able to be used, but this ship still lists a little much when the same 3 guys keep following me to other threads and posting crap behind me........and I am the problem....its cool.

.

"I humbly disagree with that statement, I have never seen the DP members more focused on this issue and working together. No posts about mine does/yours doesn't, no rehashing the same stuff we did 6-7 months ago, so far it appears to be working. I didn't start that "Conference Thread" to isolate any of the DP members from this issue, it is likely the most watched issue on the DP right now! The team could have snubbed it, continued with business as usual hashing/rehashing the same sh_t, different day, but they haven't. Read the conferencing thread, I've never seen this kind of analysis being applied to this problem. Your statement is not supported by the facts!"

JJ I know you aren't blind, several people came out openly and said they were no longer going to help, others have created bogus threads about it, or added to their sig about it. Rehashing the same stuff from 6-7 months ago? No? Take out the endless stuff about cold air intake which is a year old and half the thread goes away.....fan? thats new? water pump is new? thermostats is a new idea? Thats just the stuff I can think of right quick.

Now explain the "facts" again?

.

Its all good, maybe I can hook up with RDL if need be and get somewhere. He seems to be one of the few that can see thru BS to the meat and potatoes.

For now watching is a good time.

.