My engine temp is varying between 160*-190* pretty regularly. Doesn't matter what the weather is doing. Had the t-stat replaced about a year ago. Is there a sensor that could be causing this? Thanks for your help.

 

Does the temp go up to 190* and back down to 160* and back up while going down the road? If that is what it is doing then maybe you are just seeing the t-stat open and close the way it is suppose to.

 

My 1998 24v did the same thing. The temp would rise to about 180* then drop down to the 160* range. Did it more when the outside temps were lower. I haven't noticed my 2002 do it like the 1998 did.

Rick

 

Mine does the same and I just replaced The t- stat.

 

That is normal operating condition when not heavy towing or hauling, according to Cummins service reps.

My Bro's Cummins engine'd 18-wheeler does the same thing

Always been kinda worrysome to me - stable temps = better economy - but if Big C sez it's ok, then not to worry.

 

Mine does the same thing. However about 3/4 of the year I run a piece of cardboard in between the radiator and the charge air cooler. When running this setup, first thing in the morning my temps go up to about 200 then drop to 185-190 and stay there. No more fluctuation.
If you want to try this just make sure you cut a 6" hole about where the clutch fan is so it does not get hot and cyle alot.
CJ

 

I appreciate ya'lls help. Kind of surprised that's a normal condition.

 

mine did it with the stock caltherm 180 till this winter, tstat finally went bad so i replaced it with a stant 190, now it holds its temp between 180-190 cycling open and closed. i dont think it should run that cold (160). with the engine warm now with the 190 it sounds noticably different when idling.