klcammie

The 190 in mine heats good. I am one of those that have a small fluctuating therm. after running and everything gets up to temp neeedle settles down. Some say it is because the cooling system works so well.

KATOOM

The 180* thermostat is for the 12 valve engines. Commonly incorrectly purchased for the 98.5 Dodge Cummins too since the 12 valve engine came in the first half of the model year. Your engine would be much happier with the 190* thermostat. Better fuel mileage and better performance too.

Its a misnomer that diesels need to run cooler thermostats like gasoline engines. In actuality diesels "need" the cylinder head heat since they tend to run cooler than gasoline engines and the diesel combustion process relies completely on the heat generated through the engines compression stroke. If there isn't enough cylinder heat temp generated then the combustion process isn't as efficient and fuel mileage and power are reduced.

This problem is only exaggerated even further too as people are led to believe that diesels need cold air intake systems and huge wide open exhaust systems to make power. Yes those items can help in allowing more air flow which is necessary when adding more fuel but if those aftermarket components also force the engine to run too cool then there is little to no gain. Especially in cold weather climates.

bentwings

I was going to post about the thermostat overshoot but you guys beat me to it.

I installed a new t-stat a couple years ago and all was fine. It would go maybe 10 deg over then stabilize after about 20 minutes even in the summer. I have noticed that lately with the very cold weather it takes longer and the overshoot is greater. It was in the -15 range and I saw it go over 190 for the first time.

I thought about replacing the t-stat but it is just too cold out and I have lost my usual place to work on my truck.

My radiator is not exactly clean with 14 years of gunk from the vent tube. It still does not over heat in the summer even with the trailer.

I got lucky this year, my son is out of town and gave me his Suburban to drive so I can keep the Dodge dually out of the salt at least this winter.

duster75

My truck had 180 degree in it factory Cummin's,and had good heat and no fulctuation... now with Cummin's 190 it fulctuates. guess I better look into a winter front, have cardboard inbetween intercooler and rad. now....