Oil Temperature Probe Measures What???

I see my oil temperature probe is located in the oil filter adapter...great...got it.

So what exactly is it sensing...

-Is it sensing the oil temperature coming out of the engine before it goes to the oil cooler or...

-Is it sensing the oil temp as the oil is returning from the cooler and before the oil is reintroduced to the engine...or...

-Is it sensing oil temp as the oil is coming out of the engine until the vernatherm is closed and then after the Verntherm is directing the oil to the oil cooler the temperature sensor is sensing the oil as it returns from the oil cooler???

By looking at the oil filter adapter and the oil schematics from Lycoming and others I cannot tell...

Thanks all happy flying!!!

from another thread today...


"Just looked up a Lycoming oil flow diagram. It shows the flow from pickup -> pump -> oil cooler (or bypass thru vernatherm) -> passed oil temp sender -> filter -> on to crank case ports."

Sender is screwed into the adapter metal structure & probe bathed in oil mixed from flows from the cooler & vernatherm bypass so is probably a combinated temp of fluid & mass at that spot on the engine.

sensor is in the area downstrem of the vernatherm. When open (OT below set temp) oil flows in the housing and straight to the downstream area with OT sensor. When vernatherm closes, all oil flows to cooler then back to downstream area and OT sensor only sees this oil. Oil will be somewhat blended from two sources when V/T is between open and closed. Though, a little bit of oil always flows to the cooler and back even with the V/T open. This is why oil temps can be so low in the winter.

Larry