My 91 GL had a similar problem. I wound up replacing the oil pressure
sending unit by the H2O pump AND replacing the wire to it.  Ran like new.
Cheers
Jaime
----- Original Message -----
From: "A J I" <flavanagon@GMAIL.COM>
To: <vanagon@GERRY.VANAGON.COM>
Sent: Friday, March 13, 2009 6:53 AM
Subject: issues with oi; alarm and temp light

> On my 91 auto GL I have a recurring problem that seems to have no specific
> solution that I can find. After driving for awhile the oil light will come
> on and the alarm will sound. This will go away after a bit or if I shut
> off
> the van and sometimes if I turn a corner, There are times when the temp
> indicator will also flash but the indicator never even reaches the level
> of
> the flashing light. This too will go away with either a restart or if
> ignored will just stop. This is out of the blue both starting and stopping
> although it never happens before the motor warms up. Sometimes these will
> "go off" together sometimes not but always will quit if ingored after
> several minutes. I am thinking wiring gremlins but not sure how to wring
> out
> the system.
> I have already replaced the oil sending unit down next to the water pump,
> the old one was leaking. This motor has no oil leaks, none andis clean as
> new.I cannot see anywhere where water has or would be leaking so I am
> guessing it is a wiring bug but dont know where to look. Im guessing the
> sending unit on the top of the water reserve tank may be flaky or have a
> bad/bare wire but the wiring looks good with just a quick check. I have
> checked the ground on the firewall and it is secure. I will probably
> disconnect everything there and sand it all and reconnect but wouldnt
> think
> that would cure this problem.
> I have already removed the instrument cluster when installing the new
> master
> and checked all the contacts. Made sure they were all there and not rubbed
> or scratched off and that the contact was good so I figure that end will
> be
> good but maybe there is something else to check?
> Any help or opinions appreciated.
>
> A J