Have you tried replacing the oil pressure circuit board inside the speedo?
I've seen a few of these go bad. Also, you might want to actually verify the
oil pressure by attaching an accurate gauge in place of one of the sensors.
Should have 26 psi minimum at 2000 rpm. Oh, and are you using good quality
oil, i.e. Castrol 20W50?

Karl Mullendore
Westy Ventures
1987 Syncro Westfalia 1.9TD

----- Original Message -----

>      My 1991 VANAGON with 84,000 on the clock has been struck with the oil
> buzzer/light malady.
>
>       I have replaced the Fram filter with a Mann filter and replaced both
> pressure sensors. The problem remains, ie. after about 30 minutes of
driving
> I wll get the ligth and buzzer at highway speed. Sometimes it will stay on
> until the engine is shut off; other times it will stay on for only a few
> seconds. Occasionally I can get it to go off for a few seconds by
switching
> on or off the high beam lights.
>
>        My mechanic and I are frustrated. Any ideas on what is going on ?