I have a 1990 Jetta that is otherwise in geat shape. The oil alarm keeps going off after I ride for 5 miles or so. I took it in to my mechanic, he change them oil, changed the filter, there are no leaks. The car starts fine, then 5 miles into my ride, theoil alarm gos off.The light stays off, there is oil in the car, but the alarm goes off. The mechanic can;t find anything.

The only thing I see that is strange, is that the oil level is a bithigher than max.Before I take it back,does anyone have a theory.

thanks

John