Years ago when I had a 40 hp beetle, the oil light would flicker at idle when
it was hot.
The VW agency told me to put a can of STP in it at every oil change.
I did and it never flickered again.
He said that it didnt really do anything but give you a little piece of mind.
Thought I'd pass this on to you .   It might be worth a try.
Steve Cotsford
'84 Westy