With a completely cold engine (not running), the ECT and EOT values should be essentially the same (and close to ambient if not the same).

It's a quick (but not 100% reliable) check on the accuracy/health of the sensors.

 

Alright here we go values on a cold morning, did not start the truck.

 

 

Sorry still learning this stuff, what's OAT? Lol

 

 

Haha thanks it was about 35 degrees out.

 

Pretty confident oil cooler is crap. I drove it around and some hwy today by the time I was racing back to make it home the oil temp was 216 and coolant was 156. Was also planning on picking up a 1989 f150 with a blown tranny so I had my flat bed in tow as well.

 

Thermostat?

 

Wouldn't it keep flowing if it was a bad thermostat? In turn cooling the oil? Or via versa if it wasn't flowing then the truck would also over heat? The coolant stays cool, the oil spikes up.