Cummins ISB 6.7 360 hspwr normal engine temp range

The new 6.7's run hotter for a reason. It is due to the EPA mandated emissions equipment. Hotter = Cleaner

vanzuilekom wrote:
Hello,
I have same engine in 2008 model. On the flats at any outside temp it runs at 192-194. Climbing at 6% for 10 miles it will go to 210 and the fan kicks in and cools immediately to 195. I called Cummins and they said fan on at 210 is the spec. and 192-194 is the thermostat set point. It has been this way since day one.
Hope this helps.
Check the belt for slippage. Check the rad for dirt or obstructions. Check the coolant level and also the rad pressure cap for spring tension and seal condition.

It just turned a year old with just under 3000 miles on it. The coolant recovery bottle is within limits and the cap is checked for tightness before every trip and is fine. So hopefully the belt is tightened correctly being so new, and I really hope the radiator hasn't accumulated that much dirt as we haven't been in dusty conditions. It looks to be clean.

What are you driving and your weight? I'm at about 32,000 GCWR ( with 4,000 toad). Just wondering if a big difference in weight being moved.

And in another note that still leaves me 6,000 more lbs allowable weight I can tow within specs ( above current toad) and about 4000 more in the allowable MH GVWR. So having 6,000 more lbs hanging off the back is going to make a big difference in engine and transmission temps and additional 4,000 lbs of cargo (additional 10,000 lbs) . It just seems to be at a high temp for a light load and ambient air temps.

Hello,
I have same engine in 2008 model. On the flats at any outside temp it runs at 192-194. Climbing at 6% for 10 miles it will go to 210 and the fan kicks in and cools immediately to 195. I called Cummins and they said fan on at 210 is the spec. and 192-194 is the thermostat set point. It has been this way since day one.
Hope this helps.
Check the belt for slippage. Check the rad for dirt or obstructions. Check the coolant level and also the rad pressure cap for spring tension and seal condition.

Your temps are completely normal and fine. Also 220 is nothing for concern.

In the last couple week mine has been running 198-200 on the flats in above 90 weather.
Same engine.
Any incline and it would heat up a little until I got over the hill.

engine does not shut down at 220, but you will get an alarm. typically going up hill. Down shift to get the revs high 2000's. This will pump more coolant thru the engine.

Stopping the engine due to the alarm would be a mistake.

Better would be to see the temp climbing above 210 to 215 and down shift to high rpm before the alarm.

Engine cools faster when pumping at high revs