2003 2500hd Overheating While Towing

skippy7024 · August 3, 2009

I have a 2003 2500HD 6.0 auto trans 2wd. Normal driving the temp stays around 210. I have a 27 ft travel trailer. When towing this the temp climbs up to 230 240. as soon as I pull over, it will cool off fairly quick. I tried to flush the radiator out, it seemed to help a little, but still gets hot. I would go buy a new radiator if I knew it was the problem.

EvilWS602 · August 4, 2015

It's a brand new Acdelco radiator a month old. Had to replace it be a tank tracked.

txab · August 4, 2015

You've already got a thread going on this subject. Stick with that and don't bump other topics on same problem.

http://www.gm-trucks.com/forums/topic/175687-03-1500hd-overheating-only-while-towing/

Edited August 4, 2015 by txab

Dixon700 · July 18, 2016

Bringing an old thread back to life because I have the same issue with my '02 2500hd with the 6.0 and 4.10 gears. I just went and bought a trailer that weighs 5k lbs And had to tow it home out if Carlisle, which is tons of steep winding hills with 10mph corners. Anyways the truck has never even got warm empty. Temp stays around 190° and stayed there. First but hill I really had to get into it after the first corner because there was cars behind me wanting to go the 45mph speed limit after the corner, speed was slowly coming up and I got to the 45mph speed limit and check all the gauges and see check trans temp is up around 230° or so, and coolant temperature just about pegged. Whipped into the first place I found I could fit and let it cool down. System was holding good psi and didn't boil out the overflow until I bled the psi. Limped my way home watching temps and not letting trans or coolant get over 230°. I've read that the tiny trans cooler isn't efficient enough and am going to get one rated for 30k gvw rV's. I had removed about 2 gals of coolant and replaced with new 50/50 extended life coolant. Also added some of the coolant additive that's supposed to help run cooler. I also blew out the radiator, condenser, and coolers with compressed air then ran water through until it was clear. Tons of dirt, but would that of been enough to make it run hot with only 5k lbs behind it? As far as I know thermostat, water pump, and fan clutch are stock. Thermostat seems to work fine, and I'd imagine water pumpworks because it only got hot towing. Fan also seemed to work, would pull my shirt up against the cooler with the grill off. So just flush it out and think it was just lack of airflow? Because it never even got warm on the interstate.

txab · July 18, 2016

Check for PROPER operation of centrifugal clutch fan

Dixon700 · July 18, 2016

Check for PROPER operation of centrifugal clutch fan

What's the best way to do this? Most of the fan clutches I work on are pneumatic...

Dixon700 · July 18, 2016

I should mention there is no play in the fan, I seen no leaks or streaks off of the clutch when I had the shroud out to clean my radiator, and there is some resistance when the intended the fan. Should there only be a certain amount of turns and then it locks up? Also it may not be up to snuff. When I was climbingthat second hill my transmission was kicked way down and rpms were almost 5k when it got hot and I couldn't hear the fan, just the engine, and my exhaust is stock. So if there's any tests I can do let me know.

Dixon700 · July 18, 2016

Fan would spin about half a turn just trying to give it a quick spin. Got it up to about 200° it's normal operating temp. Grabbed a red rag and I could slow down the fan pretty good, but couldn't stop it. Shut it down and it spun like when cold so u ordered a new severe duty clutch.

txab · July 19, 2016

Fan would spin about half a turn just trying to give it a quick spin. Got it up to about 200° it's normal operating temp. Grabbed a red rag and I could slow down the fan pretty good, but couldn't stop it. Shut it down and it spun like when cold so u ordered a new severe duty clutch.

We have a winner! Next time used a rolled up newspaper to slowly push into fan

Dixon700 · July 19, 2016

Installing a bigger Hayden bar and plate tranny cooler and a carquest severe duty fan clutch tomorrow. Then I'll be putting it to work to see if it runs cooler.

Edited July 19, 2016 by Dixon700

Dixon700 · July 20, 2016

Put the truck through its paces with a couple loads this size. Tranny nor coolant got over 200° so I'll call it a successful repair.

DeStoriesAir · June 17, 2020

Having the same problem.

2003 2500HD Duramax Crew Cab, 238,000 miles.

I just got a 5th Wheel RV 4,000 lbs. I have noticed in previous years the truck starting to get hot pulling up hills. Normal running coolant temp appears to be around 203 (1 tick below 210).

The last trip I took, climbing the Arizona Mountains during the summer morning (less then 100) my temp was "overheated" as I watched it climb. I was a tick below "redine" 260 degrees and would pull over to let it cool. This happened twice. Since then I replaced the thermostats and coolant flush. That did not make a change when I tested in 105 degree weather with trailer up a gradual hill. I could of redlined it if I i wanted too.

I removed the grill and shroud and powerwashed the radiator and all the other coolers and hope to run it in 100+ temp to see if that helps.

My fan clutch when I try to spin it by hand immediately stops, there is no free wheeling (which I believe is correct).

Any other thoughts?

diyer2 · June 17, 2020

IMO

Everyone of these problems would have been avoided if properly maintained.

DeStoriesAir · June 17, 2020

Just now, diyer2 said:

IMO

Everyone of these problems would have been avoided if properly maintained.

As fluid and components were serviced regularly, this still seems to be a problem as many other have posted about it.

txab · June 17, 2020

Has the fan clutch ever been replaced in the past? Check it hot also. Many youtube videos showing how. You might look into the radiator having a passage blocked at some point

DeStoriesAir · June 19, 2020

On 6/18/2020 at 7:29 AM, DeStoriesAir said:

I have never replaced the fan clutch or water pump. I currently am disassembling to replace both.

On a side note, I did another run after I powerwashed the radiator and other coolers. I did the same run as I did before, high AC, no trailer button engaged, still pulling the same trailer. I noticed that I initially started at the tick below 210, held there for a bit, then hit 210, and ended at the tick past 217 where it seemed to hold. This is while I was pushing it hard to make it work! It is a huge difference since the run the day before (pre-power washing)! But I am still going to replace the fan clutch and water pump.

Looking for some advanced removal ideas. I am trying to get the harmonic balancer bolt out. I have the flywheel lock in place. Front the breaker bar contraption you see in the image it is still not breaking it loose. I have snapped 3 wrenches, one being a snapon breaker bar type. Any other thoughts on how to break it loose?

Thanks