Finally found my oil leak! It is from the sense plug on the side of the oil pan. Not sure if it is the electric from the oval looking larger seal having two screws on either side, or from the electric feed-through itself within this assembly. Is there a 'typical' failure mode? Is there something I might try tightning? I did try to tighten the two screw, but they were already very, very secure.

-best regards, guenter