It's a JPI probe install, secondary to the factory oil temp.
Jim

wrote in message
oups.com...

Lycomings have the temp probe in the oil screen or oil filter
adapter, at the back of the engine. I've never seen one in the front of
the case, perhaps since Lycoming specifies max oil temp entering the
engine, not halfway through it. Are you sure you need to remove that
plug?

Dan