Hey guys so my 2002 ram 2500 has been running slightly warmer overtime. No coolant loss, New radiator after a flush of the system, Fresh coolant 50/50 mix. New thermostat, new radiator cap and new water pump. Coolant is not mixed with the oil, and the truck eats no oil I just cleaned out all the bugs from the intercooler and trans cooler and ac condensor and straigtened all the fins. I am about to give up and sell it but I wanted to see if anyone out there might have any clues. The truck is a 2002 2500 Auto transmission, Airdog 100 lift pump, newer vp44 105k miles

 

Any build up of blow by oil on the back of the radiator from the tube or over full recovery tank? I had to clean mine cause it was getting plugged due to this. Passenger side, lower half mostly. Pretty common. Or perhaps an air bubble trapped in the system?
How hot does it get?

 

First off where do you live, I just moved from the cool Colorado to mesa, az and its above the 100's all the time, but I have a 50/50 mix and my truck runs about 10 degrees hotter traveling the highway and the slower I go the hotter it is. If its getting hot and its in the 70's where you are Id be looking at a possible water pump or thermostat. Some thermostats get old and no longer will open at the 180* but closer to 200 to 205. If your in the extream heat pull some coolant out and add distilled water..

 

I second the Ranch hand on pulling coolant/antifreeze and rolling more distilled water. I run a 70 water : 30 antifreeze. Also; maybe I missed it but, how hot are you getting? And it's getting hot under what type of driving? Stant makes a 180 thermostat for about 30 bucks. Make sure your lower rad hose isn't getting sucked. I would throw more water, new 180 stat, and new hoses before I'd think of selling. Try using a IR heat detector and check engine temp. Maybe a bad gauge. That's all less expensive than a new truck.

 

Where did he go?

I've heard numerous times on this forum to only use Cummins thermostats because the aftermarket ones have a very high failure rate, and keep the 190F.
Here's a pic of my old one, aftermarket 180F. The frame of it was broken. I put a Cummins one in it's place.

 

Yep. Ya cant go wrong with genuine Cummins parts. IMO its not worth it to get cheap aftermarket replacement parts, just to save a few bucks.