I'm about to buy a remanufactured long block from Fast German Auto
to solve my low oil pressure problem. As a last try before I do this I wanted to
check with the group to make sure there isn't anything I've
missed in trying to remedy the problem.

I have an '87 Westy, manual trans, a/c with about 93K miles. I bought it
with 60K miles and have been good about 5K oil changes (Mobil 1) and
flushing the coolant every two years (using VW coolant). No head
problems, replaced water pump at about 65K miles. The oil warning
light and buzzer come on after about 10 minutes of driving. Specifically
they come on when the engine speed drops below about 2500 RPM. When the
RPM's go back up, the warning stops.

Here's what I've done: took the van to VW to have the pressure
measured. They said it was low. I don't have the numbers with me but
I seem to remember 4psi at idle.  Changed oil from Mobil 1 10W-40
to Castrol 20w-50 to straight 40 weight. Each change helped in that
it took longer for the warning to to start. Have always used VW oil
filters. Had oil pressure sensors replaced. Replaced the oil pressure
regulator piston and spring, had the oil pump replaced.

Is there anything I'm missing?

Thanks very much for reading this long post!

Regards,

Jeff H.
North Carolina
'87 Westy