Oil temperature too high

All I'm saying is oil coolers unless plugged don't just stop cooling.
But a faulty oil cooler thermostat will cause high oil temps.
I'm not talking water thermostat either.

 

I am sure this is true but my oil cooler on an ISX engine started performing poorly on steep grades with a heavy load exactly as the OP describes. I would certainly check the oil cooler thermostat first but it sounds like exactly what happened to my truck. Three different shops told me it was a failing oil cooler when I described the problem. Replacing the oil cooler fixed the problem

 

I'm interested in how it could possibly fail too. Either stopped up or leaking are the only ways, both of which are indicators of other, much more serious problems.

 

I do not know but search LF9070 filters at the top right. Do those pencil eraser size pieces possibly go through the cooler before the filter and collect more particles in time because the are restricted?

 

That is my point, if it's clogged up, replacing it isn't going to fix the problem.

 

Oil always goes thru the filter last. The theory behind it is you have clean oil in the sump (pan).

 

Sounds about right. I don't think that thin tin filter case would handle 60+ PSI oil pressure.

 

Those filters are on the pressure side.
That's why the oil filter base has a bypass , so when oil is cold and thick or filters get plugged it don't starve the engine for oil.
There is no other way.

 

Sensor is just a very basic thermistor, it either works or not. I'm not sure how but the guys who say clogged cooler are really making sense. If it is clogged, find out why and fix that problem to really fix your truck.