Duramax Overheating

n5638b · January 24, 2008

I have an '03 Duramax that is overheating on me when I pull a trailer. I've done the obvious, radiator cap, fan clutch, no obstructions, etc...Runs normal when not pulling a trailer, but long hills will overheat the engine and most of the time the tranny too when pulling my trailer with a tractor on it. Then sometimes it seems that both the engine & tranny will cool down and run normal even though conditions are the same. It will do this when it is 20 degrees outside, worse when it is warmer. The worst is a long steep hill at slow speeds (20-30), the tranny will go through the roof fast when going slow, if I hit it and go fast, then the engine temp climbs to where I have to stop. Trailer weight only changes the problem in degrees. My camper (5000 pounds) has less of a problem than my gooseneck with skidsteer (total of 14,000) or gooseneck with backhoe (24,000), but even at lighter weights, the problem is still there. Any ideas?

wgabert · January 25, 2008

Just a thought. Do you have a screeen or stainless cover on the grill. remove them if you have as it may solve your problem.

jlcallaway · January 26, 2008

I have an '03 Duramax that is overheating on me when I pull a trailer. I've done the obvious, radiator cap, fan clutch, no obstructions, etc...Runs normal when not pulling a trailer, but long hills will overheat the engine and most of the time the tranny too when pulling my trailer with a tractor on it. Then sometimes it seems that both the engine & tranny will cool down and run normal even though conditions are the same. It will do this when it is 20 degrees outside, worse when it is warmer. The worst is a long steep hill at slow speeds (20-30), the tranny will go through the roof fast when going slow, if I hit it and go fast, then the engine temp climbs to where I have to stop. Trailer weight only changes the problem in degrees. My camper (5000 pounds) has less of a problem than my gooseneck with skidsteer (total of 14,000) or gooseneck with backhoe (24,000), but even at lighter weights, the problem is still there. Any ideas?

I have to believe as the over heating is effecting both the engine and transmission something is restricting the air flow in to the radiators. Stock grill?

JoJoJim

n5638b · January 27, 2008

I have an '03 Duramax that is overheating on me when I pull a trailer. I've done the obvious, radiator cap, fan clutch, no obstructions, etc...Runs normal when not pulling a trailer, but long hills will overheat the engine and most of the time the tranny too when pulling my trailer with a tractor on it. Then sometimes it seems that both the engine & tranny will cool down and run normal even though conditions are the same. It will do this when it is 20 degrees outside, worse when it is warmer. The worst is a long steep hill at slow speeds (20-30), the tranny will go through the roof fast when going slow, if I hit it and go fast, then the engine temp climbs to where I have to stop. Trailer weight only changes the problem in degrees. My camper (5000 pounds) has less of a problem than my gooseneck with skidsteer (total of 14,000) or gooseneck with backhoe (24,000), but even at lighter weights, the problem is still there. Any ideas?

I have to believe as the over heating is effecting both the engine and transmission something is restricting the air flow in to the radiators. Stock grill?

JoJoJim

Stock grill. Something blocking airflow was first thought. It is clear as a bell....