Date: Thu, 10 Jan 2008 21:22:00 -0800
Reply-To: Mark Drillock <mdrillock@COX.NET>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Mark Drillock <mdrillock@COX.NET>
Subject: Re: 88 Vanagon - oil pressure alarm
In-Reply-To: <4786D8A2.3000506@cox.net>
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When the audible oil alarm sounds only intermittently, it can be any of
several things. Very common is a problem with the oil. Also common are a
few wiring possibilities. It could even be a real problem in the engine
mechanicals.
Stop on level ground, wait a minute or 2, and carefully check the oil
dipstick. Too much oil can cause this alarm as well as too little oil.
Bad oil can also be a problem. Look at the oil for color, smell it too.
Oil Problems
1. oil too low, dropping further a during braking or turning
2. oil level too high, causing foaming at high rpm
3. oil viscosity bad, maybe wrong oil or diluted by excess fuel
All of these can be remedied for now by simply draining the oil and
putting in exactly 4 quarts of fresh 20w50. (leave filter alone) If this
fixes the warning problem, good for now. I would always consider this an
early step for this type of problem. Only $10 or so.
Wiring Problems, Common
1. loose, dirty, weak, or broken connection at the 2 pin oil switch
wiring junction on top of engine, driver's side
2. loose, dirty, weak or broken connection at the second oil pressure
switch by water pump pulley, down low.
3. pressure switch has internal connection failure
Wiring Problems, Less Common
4. bad connection on the yellow wire of the round 7 pin connector inside
the main engine compartment wiring box.
5. bad connection at the dash main relay/fuse panel. Connectors E and B
on the back of the panel carry the oil pressure signals.
6. bad connection on the 14 pin edge connector of the instrument cluster.
7. bad connection on oil pressure warning logic board hidden inside the
speedo, on the back
8. bad oil pressure warning logic board
If you have checked as best you can wiring items 1 and 2 above but the
intermittent alarm problem persists, a simple test can narrow things
down more. Find the 2 pin oil wiring junction. It will have 2 brown
wires going in on one side and both a yellow and a blue/black wire
coming out the other side. Strip away a small section of the yellow
wire's insulation. Run a length of extra wire from the now exposed inner
wire to any ground spot on the engine. If the alarm is now silent when
you would have expected it to go off, the problem must still be one of
the 3 above common wiring problems OR you have a real oil pressure
problem and it may be time to have the pressure checked by a shop. If
the alarm still goes off when the above test wire is correctly hooked
up, the cause must be in items 4-8 of the wiring problems list.
All the above assumes you have been using the van and know the normal
behavior of the led. It also assumes there is no flashing led at idle
and only occasionally at speed in conjunction with the alarm.
Mark
(tired, going to bed, proof reading not completed)