Engine/Transmission (1998.5 - 2002) Temperature guage fluctuations

[BennyHL]

My temp guage fluctuates around 190 more than I'm used to in newer vehicles with a well operating cooling system. My guage reads just under 190 when cruising and a bit lower under no throttle downhill. When I pull a hill (unloaded) I notice the temp guage climb up a little above 190. I've not noticed this before in other newer cummins trucks. I would think my engine should run the same temp no matter what hill I'm pulling unloaded. Is this normal or should I start trouble shooting my cooling system. I'm not worried yet because temp isn't near the danger zone, but I'm wondering what might happen pulling one of these hills while towing. I know my Ford n/a diesel at work gets hot pulling a long grade, but it's old, a Ford, and the cooling system has been worked to death. If it's normal and won't get above just over 190 no matter how long I pull a grade then I won't care. Thanks!

 

[klaybus]

Around 190 seems OK to me. I noticed mine usually around 180+ going to 190 under a heavy foot or a hill. Keep an eye on it but I think your fine. For piece of mind you could always flush your system until it drains clear, and then install new coolant with a new thermostat.



Clay

 

[John - K5AWO]

If you do replace the thermostat, use only a Cummins part or Mopar. Stay away from the aftermarket crowd, they perform just exactly like you are describing.

 

[DDT]

That is how mine did. 190 + empty ans loaded. I had the rad cored, 44 tubes out of 90 were plugged. A new 180 thermostat and WOW cab is quieter. Mine does have 125K on it.

 

[pgleavitt]

I just flushed my cooling system(used flush from Cat. dealer,great stuff) and new thermostat from cummins and see the same as you. Filled it up with the ELC from fleetguard. Stayed right at 190* pulling a 10,000 lb. concrete pump up steep hills,air cond. on and outside air temp. 87* No problems.

 

[BennyHL]

Thanks for the responses guys. I'm not concerned about the 190*, just the fluctuations on hills and under hard throttle while empty. I'll keep an eye on it and sooner or later I'll tear into everything and check it out. Thanks!