When im not loaded driving around in 100+ degree weather with the ac blowing the temp is at normal.....

When im pulling my trailer and jeep, its roughly 8K pounds. its fine in the flats but when i hit a grade the temps starts slowly rising , the longer the grade the hotter it gets i have hit the red a few times. but when i get to the top it cools down pretty quickly.

any ideas? antifreeze looks nice and green, fan clutch seems to be in good condition... please help.... thanks. Kodi

 

Norkal, I had an identical problem with my 95 with 185k. Long story short, I replaced my radiator (it was original equipment) and haven't had a problem with it since. You may want to look at the coolant system flush link below (it has pictures) before changing the radiator. I also replaced the thermostat. The only problem with the thermostat is that it goes to 190, opens the thermostat, goes down to 140, goes up to 190, down to 150, etc, etc. until if finally settles out after 5-6 cycles. I understand that there is a thermostat available that stops this, but it isn't high on my priority list. Also make sure you get all the air out of the system.

https://www.dieseltruckresource.com/...=coolant+flush

 

spray out your radiator with water from both sides, you'll be amazed how much trash is stuck to it.

 

Better yet, take it out of the truck and clean it. Much better results and not that difficult.

 

Something also if your TC isn't locked up when pulling the hill you'd be surprised how much heat a factory tranny will up your temps through the heat exchanger under the exhaust manifold.

Or at least thats the prob my 97 has when in the lower gears pullin a hill.

 

Could this happen even if my transmission temp doesnt ever get over 190*?

 

The heat exchanger under the exhaust manifold is for engine oil. The transmission fluid is cooled in the radiator, and both will make the engine water temps rise.

 

Ocmechanx is correct. Th autos have a double cooler system. The first is a heater/cooler that uses engine coolant/A-F. The front cooler is a separate unit and mounted next to the A/C condensor forward of the I/C and rad.

Norkle
As far as 190° tranny temps. If you are measuring temp from the pan it could be a problem. If sensor is in hot line to coolers that is fine.

I'm thinking your fan clutch is not good. When they lock-up the roar is deafening in the cab.

 

The oil cooler is behind the oil filter,
The ATF to engine coolant cooler/heater is further back and down.

 

I'll be darned, learned something today. I'll add it to my reasons for vowing never to own another diesel/auto combo.