RE: Oil Pressure Light
Anna, you should get this resolved and drive as little as possible until you
do.
First, you may have overfilled the oil and that is not a good idea, the oil
level should be between the two marks and never above the top one.
Two questions to get answered:  What weight oil is in the engine and what
make filter?  You should be running 20/50 weight oil (for standard oil) or
15/50 if synthetic. And the filter should be from Mahle or Mann.
The first thing I'd do is get the Vanagon to a good Vanagon mechanic and
change to oil to make sure it's the right amount and right weight.  And
change the filter to one that is known to be good.  If the problem persists
then further diagnosis is needed.