Hello, all.

A few weeks ago, my Westy's oil light started flickering quickly and
irregularly.  It would flicker on and off three times in about a second
and a half, and then would not flicker for an irregular amount of
time... maybe fifteen minutes to an hour between these brief episodes.
The oil stick always registered that the oil level was good.  I didn't
see any signs of overheating.

I took it to a local mechanic.  He said the his guages were reporting
that the oil pressure was about 8, which was seriously low.  He felt
that the oil pump was good.  He replaced the oil switch and felt that
would solve the problem.

A day later, I don't get any flickering of the oil light, but the oil
light flashes on and off when the van is idling or the RPM's are low.
Coming down a hill yesterday with my foot off the accelerator, the oil
light flashed on and off.  I downshifted the automatic tranny to 2nd
gear, causing the RPM's to increase, and the oil light stayed off.

When I did my last oil change, they put in 20-50 viscosity oil.

Any insights into this problem?  Is the oil too thin for the season?

It's a 1990 Vanagon Multivan with an automatic transmission used for
running around Western half of Washington State.  The daytime temps
have often ranged from 78 degrees to 90 degrees.

- Ken