My oil temp sensor is at the oil pan but I am currently adding a second sensor where the oil exits the coolers. I'll run both sensor leads thru a switch I can activate at the dash allowing me to see either oil temp; before or after being cooled. I run two oil coolers. The primary cooler always has water flowing thru it and the other allows forced water flow which is noticeable above 20 MPH. Oil flow is controlled with a thermostat and the oil is piped thru the two coolers in series. Adding the second oil temp sensor should give me a good idea of how effective the coolers are...especially the second cooler with the forced water flow.
"1978" F-22; Turbo'd & Intercooled.