1998.5 Cummins Deisel. New Rad, New Water Pump, New Thermostat, New Fan Clutch. The stupid thing still overheats in overdrive when I pull my camper. When I take it out of overdrive it cools right back down to about 220 (just out of the red) it runs a little warm when I'm not towing anything.

Does anyone know what might be causing the problem? Do these things have temp guage sensors or sensors on the tranny that could casue this? I'm not sure it's not just my guage reading wrong.....I'm at my wits end now!!

Please Help,
Thanks

 

do you have an internal cooler to the radiator for the tranny? your OD might be causing the tranny fluid to get hot... that would be my 1st guess...

the AT is a weak spot (OD) on that truck, you might wanto get it serviced if it hasnt been done lately...

 

i do have an oversize cooller on it.What aboutthe guage sending unit? Tranismission on has about 30k miles on it.

 

I used to have the same truck. When I replaced the radiator, the new one was half the core thickness. Maybe you got the same deal. The origional one was as thick as the tanks. New one was much thinner. I never drove it under any stress afterward but I didn't think that seemed right.

 

I agree with Steve. Trans is the cause.

 

Truck temp guage still acts funny. It now will go back and forth from pegged hot at 240 and then go back to about 210-220 while towing the camper in drive. I drove it home from the mountains this weekend. The last 65 miles the temp guage stayed pegged on hot. It really can't be overheating or the thing would have blowed sky high by now. I done this on several trips and it's never actullaly overheated.

Any tips??

I'm beginning to wonder if the guage is bad or if there is a sensor or something I should replace.

Thanks

 

after reading this 4 things come to my mind
the new radiator is smaller then the stock one
wrong thermostat for your engine
trans is overheating causing the water temp to rise
water temp switch is messed up

Check this out Old school trick here when its over heating try turning the heat on high and see if the temp goes down. if it does temp switch is reading
since you have a new radiator did you check to see if it was 50/50 mix? that will cause the boil over point to be lower if you have to much water.
Or someone just gave you the wrong thermostat for your truck.
I think its the trans its overheating when you drive in OD and hauling your trailer ITS SHOWING ITS AGE. look to get a trans rebuilt if thats the case
thanks Pizzo

 

I thought for sure that antifreeze lowers the boiling point but increases the freezing point, & for optimal cooling, you want the minimum amount of antifreeze needed for the area that you live in. I remember reading this in a few places over time, including Water Wetter literature.

PS: pizzo, you've got the same insanely red dually that I have! Bright, isn't it???

 

I have always been told to have a 50/50 mix. To cover boil over point and freezing point. If I'm wrong opps. with a good radiator cap too. This guy I think the trans is overheating because he is towing when it over heats when he uses OD when he tows then when he takes it out of OD it cools off. but wouldn't checking everything else first be more logical then putting 4 thousand into a new trans???

Yes my truck is bright red. the funny part is going into a grocery store and a little 3-5 year old says LOOK MOMMY A FIRE TRUCK lmfao I almost wet myself on that one