oil temperature

[jeffn]

Yesterday, I drove back to South Florida from Alabama. 710 miles, unloaded. Watching my gauges I saw the oil temperature climb to 205 and abruptly drop to 183, then start the slow climb to 205. Rinse, repeat for the entire drive. Coolant stayed constant at 187-190, transmission at 167.

I have never seen it do this before. It typically loads up to 10-15 degrees above the coolant temperature and stays there. I have read about the system not using an actual sensor. Have you seen this cycle in your truck, or does the oil temp stay constant?

 

[dslbrnr]

Jeffn I don't see your truck Signature but I have an HO/Aisin, my oil temp drops but usually shortly after exiting the freeway. My oil temp doesn't cycle up down like yours but stays around 190-200. I think my oil temp has gone over 205 before it starts to drop. Not sure what temperature triggers the oil cooler to open

 

[jeffn]

Jeffn I don't see your truck Signature but I have an HO/Aisin, my oil temp drops but usually shortly after exiting the freeway. My oil temp doesn't cycle up down like yours but stays around 190-200. I think my oil temp has gone over 205 before it starts to drop. Not sure what temperature triggers the oil cooler to open

thanks. 2020 HO.

This behavior is not uncommon, based on my research. Oil temperature is one of the least problematic indicators in these engines, the internal oil cooler works well. I tow heavy, but this is Florida so grades are not a factor in towing.

 

[jsalbre]

IIRC, the Cummins doesn’t have an oil temperature sensor, the number you see is a calculated value, and may or may not be accurate.

 

[OLEJOE]

My 22 and my 18 both did the same thing. The 18 would stay up around 200 until I stopped on an off ramp and immediately drop to 165 and start creeping up until I stopped again. Normal oil temperature should run around 10 degrees higher than coolant. As far as I know, the oil cooler doesn’t have a thermostat. It’s also used to help heat the oil when it’s cold from the coolant.

 

[tchur1]

The oil temp gauge is just an algorithm, not an actual reading so its is directionally accurate but not a true reading on oil temp. The only actual temps are coolant and trans I believe.

The behavior you outline is very similar to what my truck will do when towing, I don't worry about it at all.

 

[AH64ID]

The oil temp gauge is just an algorithm, not an actual reading so its is directionally accurate but not a true reading on oil temp. The only actual temps are coolant and trans I believe.

The behavior you outline is very similar to what my truck will do when towing, I don't worry about it at all.

Exactly, oil temp and oil pressure are algorithm based readings and can/should be ignored.