Hi I have a 2001 2500 dodge diesel that everytime I tow even 1500 lbs or more it jumps up to 220 degrees I have had the tranny rebuilt at 130000 miles and the themostat changed. Blown out the radiator every week,Without towing truck does fine ,up hill will jump to 210 , any help or simalar problems solved???

 

My 12 valve does tha same thing, it is your thermostat according to most diesel mechanics.

 

Might try a new fan clutch. Those don't last forever, and shouldn't be to pricey.

 

Sounds to me like your rad. is partially clogged. Any good rad. shop can flush it for you, & tell you if it is clogged or not. Good luck.