No, I am not having issues with overheating.

I'm just wondering if anyone here has had a "heating up" issue with their Cummins powered Dodge when towing in any weather while towing within the specified limits (or not). I've been doing some reading on RV.net and other forums where many LLY Duramax owners use the line "any truck will overheat when asked to tow heavy loads in hot weather... blah blah". I just don't buy it.

I think that the LLY Duramaxes overheat because they were poorly designed by their engineers.

So, any Dodge/Cummins truck overheating, come close?

I know my 2nd gen truck got warm when towing when I first got it, then I took the rad out and washed the brown fuzzy sweater it was wearing off of the rad, and all was well. I towed 2500# over the 16,000 GCW limit for a 3.55/47RE/S.O Cummins, and never had an issue. I did get it to 3/4 on the gauge once, climbing a steep hill at very slow speeds (~25 mph due to people walking on the roadside on the twisty 2 lane mountain grade - Lake Louise for those of you that may know it - heck, there's a warning sign at the bottom saying that oversize vehicles and trucks w/trailers should not attempt it, but I did anyway). I was at 18,500# GCW, and it was 85 - 90* out that day. man did the cooling fan ROAR!

What say you?

 

I have had no issues and also have ran the crap out of it on a 6-7% grade right out of Asheville on I-26. It is normal for it to go a little over the hash mark in the middle. My Quad temp gauge only reads 200 deg at that point. No it is not common at all to overheat our trucks, not at all. 3rd Gens that is.

 

I have gotten a needle width or 2 over the center mark of the gauge on steep grades of 6-8% in outside temps well over 100*s, was running AC at the time as well. My EGT's were at about 1K.

I have been considering doing the heater core bypass, it possibly might help to lower the temps a little, certainly seems to make the AC cooler for those who have done the bypass. My AC is VERY cold and operates just fine, even in those 100*+ grades I have to set the blower switch down, gets too cold in the cab.

I have also considered installing a coolant filter, you get some aux cooling from the filter and air blowing on it.

CD

 

None with my Dodge. I've never even heard the fan engage.

I read a lot of the overheating issues with the LLY. I had an '03 Duramax (LLY), hauling my 4,000 lb camper, 6% grades for miles in almost 100 degree weather and it never overheated. The fan would engage/disengage a lot but engine temp stayed normal. It seems some LLYs have the problem and some don't. Glad I don't worry about it with the Dodge though.

 

Towing my truck camper/trailer/jeep(about 10k) I can hit the upper limit of the temp guage in hot weather on a LONG extended climb, like HWY 93 going into Radium BC. EGTs around 1000, tranny temps about 180. Nearing the top I have to back out cause the engine is getting hot. This is with 300,000kms on the engine plus mods, I keep meaning to pull the rad and get it cleaned....

For comparison my buddy has a 2005 3/4ton SB Dodge diesel. Pulls a similar load but has a smaller camper, lighter truck, same trailer but lighter Jeep. So maybe 2000-2500# lighter than me? Truck is stock and he has no problems keeping up to me and his temp gauge never budges.

I saw a funny home video where a guy loaded a budget truck onto gooseneck and then hooked up his Duramax and went driving in the mountains and filmed the temp guage. Got smoked by a 2nd gen Dodge hauling a 5th wheel cause the dmax kept overheating and derating its power.

 

I tow a 17K trailer and even in 100+ deg. temp I have only seen 200-215* water temps.I also keep my cooling system tip top!

 

Last year during harvest I was at about 42K and it was 109 and the the engine ran its normal temp. Cooling fan was running most of the time. When I stopped for fuel I saw a Duramacx pulling off his bug screen, just pulling a small camper.

 

Friend had a '99 5.9 and sitting for extended time it would get hot. I yanked the radiator and cleaned all the junk out of the fins. About 50% of it was blocked. After that it never had a problem again.

Tobin

 

LLY did not start till 04.5. You had an LB7. The LB7 had a wastegate that would prevent the induction heatsoak that leads to the LLY load-induced induction overheat.

Small world Ian.

 

Yep, my mistake. Chevy was an '05. I remembered the engine code better than the year.

 

98 12 vlave. 13,000 gross up a 7% 18 mile grade. Mid August last year here in the desert. 100+ degrees. Coolant never got over 205, and I never got under 55mph.

Love this truck, and that was before any mods!

 

My dad says he has overheated a few times but I don't have any specifics. His truck is a 1990. He told me the dealer he took it to got it to overheat and then they put in a 1991 radiator and then they couldn't get it to overheat. They then put his radiator back in and told him everything was OK. Typical dealer line. I know he has never been stranded from it heating up though.

His 5 speed tranny though that is another story.

 

You don't have to pull your radiator to clean it. Just spray the fan side with degreaser and wash it off with a garden sprayer.

The upper limit on the gauge is like 245*F And I don't have an automatic, but 180* seems high too!

Do us all a favor and wash that radiator!

........Jim

 

Pulling 11.7K lbs high profile fifth wheel thru the hills around San Antonio I finally heard the fan kick in, but never got hot. I never even heard the fan kick into high on the flats.

 

I pull a boat and trailer(10.5K) with my 04.5 3/4T 4x4 Dodge diesel auto and during the summer here in Austin(100+*) up and down hills the temp gauge is over 200. Trans temp is about 180 and going uphill the EGT is sometimes about 1300 to 1350. Truck has 92K.
Jay