Morning,

I have a 150k mile 1988 Vette with the engine oil cooler. I run a 180 degree thermostat and 10w30 full synthetic oil.

With cooler installed, after steady 75MPH highway drive for about 15 miles, oil temp would get to about 212-215 (coolant was about 180).

I bypassed cooler (because PO crossthreaded filter on to it and I couldnt get it off) and now after same drive, my oil temp stabilizes about 229-231. 

Just sharing the results which indicate the oil cooler does help keep oil temps lower.

Cheers,

Chris

Good to know, I have often wondered how much difference it made.

Thanks

Garry