OT - Dodge Diesel Overheating

Bill VA · Oct 29, 2016

Had a friend come yesterday to pick up a load of hay with a Dodge 3500 flatbed, 2 wheel drive and Cummins diesel. Don't know the year, but believe this is the 3rd generation model truck model that offered Cummins. We're in the mountains and he mentioned he was surprised it didn't overheat coming out, even empty.

Are these Dodge trucks with Cummins diesels prone to overheat? Just getting into this, but am going to try to help with some trouble shooting for him. As far as I can tell, the truck is in great shape, well maintained and low mileage.

Dodge + Cummins = overheating?

Thanks,
Bill

JD Seller · Oct 29, 2016

They are not prone to overheating. I won four Doges and none of them over heat without some thing being wrong. The first thing I would do is wash the radiator out. even if it looks clean wash it with some type of soap. A thin film of road grim and or oil/diesel will effect the radiator's ability to cool. I use just a garden hose and hot water out of my water heater.
Also check and see if the fan seems to lock up when the motor is hot. I have seen fan clutches be bad that slip even when the engine is hot therefore they will not pull the air needed.

ASEguy · Oct 29, 2016

They were not prone to overheating from my experience. I have found the radiator fins covered in a mat of bugs/organic material which can cause them to run hotter. Check the front of the radiator and spray it down to the ground. May even need to spray from the back forward.

300jk · Oct 29, 2016

I own a 2007 with the 5.9 cummins. 230,000 miles. Has never overheated even pulling our 30' camper or 24' goose neck on 90 degree plus days. The front cooler is for the air conditioning if the truck has it. That cooler has small fine fins and is very prone to getting plugged up with bugs and having the fins get bent over from normal use. Like others have said keeping it clean is important. I also have a fin straightener to fix the ones that are bent over. Bent fins equals little air flow.

RedGreenGuy · Oct 29, 2016

Mine got hot on long pulls. washed radiator both directions. Used flash light after dark to check if radiator fins were open. Replaced fan clutch problem solved.

smallercrawler · Oct 29, 2016

Bought a new 2004 Dodge dually/5.9 Cummins/6 manual/4wd, now at 202 kmiles, never had an overheat condition despite some long mountain trips with 10k# trailer on 90+ degree days. Nothing engine related; 2 clutches (1 cheapy/readily available, then the good one I should have waited on).

Rons b · Oct 29, 2016

I had one overheat because of a bad water pump. They made 2 types of pump, an open impeller and closed impeller. the open impeller wears against the pump housing then can't pump enough to cool. I installed a new closed impeller pump. problem solved. As others said check the radiator and fan clutch first.

MT RON · Oct 29, 2016

The early dodge 12 valve's,89 & 90 had a 2 core down flow radiator & both top & bottom hoses were the same side of the radiator,thus only about a third of it was cooling.I know because I had one and finally had to put in a 3 core crossflow radiator.That was the end of problem.Ive had a 99 24 valve for years and never a heating problem.

Nick m · Oct 30, 2016

I've had 4 different ones. A 91,97, and two 01's. Not one ever overheated. Had a problem with one 01 not building enough heat. Changed a thermostat and good to go.

JBDyer · Oct 30, 2016

I know nothing about mountains, but I know everything about hot weather, I am in Texas, My '96 never overheats, Its the first diesel truck I have ever owned and the first truck I can run the AC while loading hay. This Cummins/Dodge is a pretty good truck if maintained, mine has around 250,000 miles and I used to be a diehard Chevy man, you couldn't give me a Dodge gasser, but that Cummins is a good engine And believe me it gets HOT here!

OT - Dodge Diesel Overheating

Bill VA

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JD Seller

Well-known Member

ASEguy

Well-known Member

300jk

Well-known Member

RedGreenGuy

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smallercrawler

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Rons b

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MT RON

Member

Nick m

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JBDyer

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