I have been having a problem with our 05 GMC, 3500, DRW,CC, Auto, overheating on the last 2 trips we have been on this month. The truck only has 15K miles on it, pulling a new, non L/Q, 4 horse Trails West Sierra, that weighs 6400# with 3 avg. 1200lb. geldings. I replaced a 03 model, same exact truck with 70K miles on it with never a problem. Has anyone out there experienced this with their Duramax ?? Normal weather, 80-85, normal road conditions for this time of year, the dealership cannot figure it out. I would greatly appreciate any & all feedback on similar problems,,, Happy Tails.

Nope, no problems with my '04 Dmax and hauling last weekend in 95 degree heat, made me wonder, but no problems. Your truck is still under warranty, best to have it checked out now!

And yes, to the previous post, the Duramax is a diesel.

Ours is a 2001. Haven't had to do anything to it but general maintanance. It has 79K miles on it.

just curious, is your truck stock?  tires, grill, winch, chip, exhaust etc????

personally i am less than amused with the latest diesel offerings from the big three.  the horsepower wars have fuel milage in the toilet.  gm has some STUPID problems with the dmax, ford has the 6.0, dodge/cummins seems to be doing good right now, have to see how bad they screw up a good thing with the new cummins.  maybe its just growing pains?????

Not real familiar with Duramax, but what kind of cooling fan does it have ? how big is the trans cooler ?

I know if the Allison is stop and go it will heat up and then heat the radiator I experimented on a couple of trucks and installed a electric fan on the front to blow air through and had a switch to turn it on and off.When it would start to heat up, hit the fan and it cooled off.Not sure what temp the chevy fan is set for.

On My Ford F350 I can hear the fan come on when it starts to warm up.The temp gauge doesn't move.Sounds like a siren.

I hate it when the dealer cant fix something...I think it is because There are no MECHANICS working at the dealers just technicians.The difference is a Mechanic will tear something apart to see why it failed, a tech will just replace it and then you never really know how the problem can be solved.

I did notice the last sensor I purchased for a Cummins they wanted the old one back, had a deposit on it,they said it was because they wanted to tear it open and determine why they fail.

It's strange why some trucks no matter what brand have problems and another truck of the same brand won't

It's like your truck..why is it getting hot,poor circulation,poor heat dispersal,cooling fan not working properly,trans disipating heat into radiator,what the @#%^*&* is goin on here.Will be following the thread to see what you find out.good LUCK.

I have 05 3500 Duramax. when I pull a trailer it gets hot quickly. I changed thermostats it has 2. A new water pump and fan clutch. I cleaned out the area between ac and radiator. I didn’t use dealership but a very good mechanic. A new radiator is next? I’m at the end of my rope? I luv the truck but it’s not useable.  Any other ideas you might have are welcome.

Originally written by Ropehorse on 2006-07-20 7:31 PM

Hi gang sorry for the delay in getting back to your questions. Yes, the truck is totally stock, no chip, exhaust, etc; The fan is working properly, no coolant loss anywhere, I do not think the dealership is dumb, just as stated prior, "most" of the new age people are technicians not mechanics. With all of the new technology in today's trucks I know it can not be as easy to diagnose something as it used to be in the good old days, BUT, there should still be a technical way to establish the problem. If they are gonna sell'em they better know how to work on'em !! Thank you everyone for your feedback, please let me know if you hear of any new developments or cures,,,,

I agree!

Personally the duramax will run warm.  Its not designed to pull and run cool.  I have owned 5.  All of them did it.  They drop out of 6th gear and run 3k+ rpm.  Way to high for me.  Fan clutch in the Dmax is notorius for staying on sucking fuel down while doing it and also makes a HELL of alot of noise.  All of this is the reason I dont pull with them anymore.  Switched from them to 4400IH now to a dodge.  I have had little to no problems with those two pulling same loads.  Several folks in NM this year that had DMax complained about temps.  in fact most of them complained about that alone.  Didnt hear of many other complaints with them.

My 05 would run 235 in march when it was 70 outside pulling mild grades.  I had seen egt as high as 1350 with edge controller.  And NO it was on stock.  I ruined two of them from having them jacked up and towing large loads for excessive miles without cooling them down. 

The Dmax isnt for me.  Others swear by them but I personally will not own another until they can prove otherwise for work.  Not play, not fuel, not whatever...

All of them have problems all of them say theirs is best.  NONE of them are worth the money we pay for them.