@Marc Orloff, I have a Mocal sandwich between my oil filter and the mount. It acts as an automatic switch to send oil to the cooler when it exceeds a certain temperature.
Also, I have a switch on the outlet of the cooler that turns on the fan when the oil coming out of the cooler exceeds a certain temperature.
I have a light in my combo gauge that tells me when the fan is on. I think a lot of the time oil is going through the cooler but the fan hasn't come on.