Had a bizarre engine temp issue on way home from Reno,Nv

[Bug Out]

I was on my way back from a trip to San francisco bay area , to Reno, and back to phoenix the last week with my 40' RV in tow. RV weight approx 16.5K on this trip. On the last 150 miles thru Nevada towards Vegas and on to Kingman,Az my engine temps were running around 215 to 225 and the clutch fan was not kicking in until 226+ degrees.

I have owned 4 of these 4th Gen RAMS CTD and almost all of them never ran over 217-220 without the clutch fan kicking in and cooling it to 200 or so. This truck has done the same thing up until this leg of the trip.
I called a dealer and of course they have no one available to check it until the next day etc.

I decide to continue towards Phoenix and use the heater to cool the motor if needed. At one point, the engine got to 226 and I used the heater to cool it down, and it went back to 210-215. I made it to kingman,Az and got fuel/food and let it sit for 20 minutes, engine off.

Started it back up ,got on the I-40 and everything was fine, clutch fan kicking in at 217, never got past 220 and motor would cool off fine,. Ambient temp was 102 when I first noticed the issue in Nevada and at 102 climbing a hill in Az did fine.

I have pulled the same RV even heavier up 6% grades in 110 degrees on previous trips and never saw temps like that..

Is it even remotely possible the ECM had some kind of a hiccup and temps were reading wrong, or ever hear of anything like this before?

TIA

 

[TCDiesel]

Yes, I have seen the EVIC +-8-12F form actual, At Times I will look at the data when in Stationary De-soot (40-80 minutes things get hot) and the EVIC is off form actual readings...At times the System will use oil temp AC Input and other sensors Etc.

I find it odd that the heater core was able to cool it down in that heat.

 

[Bug Out]

Yes, I have seen the EVIC +-8-12F form actual, At Times I will look at the data when in Stationary De-soot (40-80 minutes things get hot) and the EVIC is off form actual readings...At times the System will use oil temp AC Input and other sensors Etc.

I find it odd that the heater core was able to cool it down in that heat.

That would make sense. I have used the heater cool down deal since high school when i owned junk cars,. Pulls 20 degree's off usually, unless fluid is gone. My 2005 5.9 dually , I had to do that whenever pulling a long hill when the same trailer. A/C off, heat on full, blower on high. It gets mighty hot in the cab, but works....

 

[TCDiesel]

That would make sense. I have used the heater cool down deal since high school when i owned junk cars,. Pulls 20 degree's off usually, unless fluid is gone. My 2005 5.9 dually , I had to do that whenever pulling a long hill when the same trailer. A/C off, heat on full, blower on high. It gets mighty hot in the cab, but works....

WOW........
Bug out , I would carry another thermostat...Just in case, The use of the Heater opens another passage for the coolant to travel back into the system, My guess this will cool more then the Heater core.