Date: Mon, 20 Aug 2012 15:27:16 -0400
Reply-To: Steven Sittser <ssittservl@AOL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Steven Sittser <ssittservl@AOL.COM>
Subject: Re: Oil pressure light and buzzer
In-Reply-To: <8CEEBCDFA9033B5-6F4-4497A@webmail-m101.sysops.aol.com>
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Well, it took me 4 months, but I finally tried the fixes described
below. Results: nothing helped.
First, I replaced both oil pressure sensors. (I tried to do it myself,
but couldn't manage the one near the water pump after a couple of hours
of trying. So I took it to a shop - they found it very difficult, but
managed.) I also replaced the wiring leading to the sensors, right up
to about the point that they enter the engine compartment. The old
wire to the low-pressure sensor (between the push rod tubes) had broken
(I think at a splice someone had put in long ago), and the wiring to
the high pressure sensor (near the water pump) had brittle insulation
in places. (I couldn't find any brown wire - the proper color - so my
daughter colored some blue wire brown for me with a Sharpie pen.)
I had wondered if perhaps the old high-pressure sensor had the wrong
pressure rating, once it was out, I examined it, and it had the proper
rating. Oh, and the broken wire to the low pressure sensor was not (I
believe) a contributing factor to my problem: since that switch is
closed when pressure is low, and open when pressure is good, the broken
wire resulted in a constant "pressure is good" signal from that switch.
Presumably it also caused my oil pressure light to not blink on
start-up, but I never noticed.
Anyway, after this, the result was: no change. Things were maybe even
a little worse. The oil pressure light and buzzer seemed to come on at
least as often, and maybe even more often (see way below for original
problem description). I drove it for a few days this way to make sure.
Next step: change from a Fram filter to a German filter. I changed the
oil, and installed a Mahle filter from Bus Depot. I used Valvoline
MaxLife semi-synthetic 20W50. The oil level is about 2/3 of the way
from the "low" mark to the "full" mark.
Result: no change. The oil buzzer and light still come on when I
decelerate from highway speeds, if the weather's warm (today's about 80
degrees and it happened).
So, some remaining causes I can think of are:
(1) Bad oil pressure computer (the thing that examines the switches and
the RPM's to decide to light the light). But, GoWesty's article on the
oil pressure warning says, "The computer ... is almost NEVER bad."
Also, I'm not sure it would fit the symptoms: I assume the pressure
switches are either open or closed (as opposed to, for example, varying
their resistance with the pressure), so the computer would have to end
up saying something like, "because the van has just dropped from high
RPM's to low RPM's on a hot day, I will ignore the open circuit on the
high-pressure switch line and act like it's grounded, indicating low
pressure". That sounds like an awfully complex failure.
(2) Truly bad oil pressure, due to some engine problem. But the engine
is a rebuilt from about 6 years ago, and it's been (supposedly)
thoroughly overhauled since then, though my confidence in the shop that
did the overhaul is not high. I would be more suspicious of that most
recent work, except my van has had oil buzzer problems intermittently
in the past, too, before it was done. Sometimes that was just a loose
connector, though.
(3) Maybe the van doesn't like the oil I'm using? But the weight's OK.
Other than problems in the idle control system (not boosting idle for
A/C, etc.), which I've described in other posts, the engine seems to be
running reasonably well.
I'm tempted to replace the high-pressure (0.9 bar) switch with a
slightly lower-pressure one, in case the problem is marginal but
adequate pressure. If it weren't so hard to get to that switch, I'd
probably try it.
I would welcome any advice. Thanks!
- Steven Sittser
-----Original Message-----
From: Steven Sittser <ssittservl@AOL.COM>
To: vanagon <vanagon@GERRY.VANAGON.COM>
Sent: Wed, Apr 18, 2012 6:19 pm
Subject: Re: Oil pressure light and buzzer
Two oil pressure sensors (one high, one low) are on their way from Bus
Depot, along with 4 Mann or Mahle filters.
I'm curious if just replacing the high-pressure sensor would fix the
problem. Assuming I can manage to get to it, if I unscrew it, will oil
pour out the hole (lots, not just a few drips)? If so, then I'd want
to drain the oil first, in which case I'd replace the sensor and the
filter at the same time - I don't want to change the oil twice. But,
it would be less experimentally interesting to change both the filter
and the sensor at the same time.
- Steven Sittser
-----Original Message-----
From: Steven Sittser <ssittservl@aol.com>
To: vanagon <vanagon@gerry.vanagon.com>
Sent: Tue, Apr 10, 2012 1:39 pm
Subject: Re: Oil pressure light and buzzer
Thanks for the advice.
Jeff Schwaia said:
> [make] sure you do not have too much oil in your engine. The
> level should be between the lines, NOT AT THE TOP LINE.
> When the wbx'er has too oil, the crankshaft will splash the oil in the
> crankcase on every revolution. This causes the oil to get frothy
(tons of
> little bubbles) and oil pressure will drop.
I checked; my oil level's about 75% of the way between the two marks.
David Beierl said:
> Begin by unplugging the sender wire from the sender on the after face
> of the engine, just left of the crank pulley. Then run the engine
> and see what happens. What *should* happen is that with engine
> stopped, key on, you'll see blinking light but no buzzer. After you
> start, no light or buzzer until ~2000 rpm. Above that the light and
> buzzer should come on.
I tried this, and the the light and buzzer behaved as they are supposed
to.
Key on, engine off: blinking light
Below ~2000 RPM: no light or buzzer
Above ~2000 RPM: blinking light and buzzer
Drop back below ~2000 RPM: blinking light and buzzer both remain on
So, apparently the light and buzzer "latch" once on, and don't go off
even if the RPM's drop below ~2000.
I'm curious whether the buzzer and light would stay on if I had
reconnected
the sender wire at >2000 RPM (simulating "pressure is OK now"). I
wasn't
quite curious enough to stick my hand through the whirling belts
o'death to
try it, though. I may rig up a remote switch and try again.
Dennis Haynes said:
> Once the logic board activates the buzzer it will stay on regardless
of
> engine RPM. The only way to silence it is to get the pressure switch
> satisfied or cycle the ignition switch
That fits with what I found in David's test above. I still should
probably
check that satisfying the pressure switch will turn off my light and
buzzer
as it's supposed to, but, based on on-the-road behavior, I suspect that
works:
otherwise, the only way I could get the buzzer off would be to shut off
the engine, and that's not (quite) the case.
Dennis Haynes said:
> What is most likely happening is that after a high speed run the oil
is getting
> to hot or there is some other pressure problem or maybe the switch is
out of
> tolerance. But as the RPMS drop so will the oil pressure and near the
2,000
> rpm range the warning is activated and then remains on even down to
idle.
> Revving the engine above 2,000 rpm then raises the oil pressure
enough to
> satisfy the switch and the buzzer turns off.
That sounds like it would explain my symptoms. So, perhaps my buzzer
and
light aren't really, as they seemed to, coming on at less than 2000
RPM, but
are coming on just above 2000 RPM, and then staying on at less than
2000 RPM.
Scott Daniel said:
> many waterboxers will run just fine ..until oil clearances are so
large
> that oil pressure starts being an issue..
> always when hot of course.
> At some point it's time to retire or rebuild the engine before it just
> blows...like rod through the block.
The engine was replaced with a rebuilt one in 2006, and recently
overhauled, so I'd like to think that's not an issue. But you never
know.
When I had my original engine rebuilt by a supposed Volkswagen expert,
it threw a rod through the block within a few months. (Thus the
replacement. That was an adventure - the shop that did the rebuild had
gone out of business in the interim, and the attitude of the owner was,
"it's not my problem - it was working great when it left the shop.")
Scott Daniel said:
> I'd just check the real oil pressure .. like with a gauge.
An excellent idea, but complex enough that I think I'll try simpler
solutions
first. (Unless there's an easy way to do this that I don't know about.)
John Rodgers said:
> Running with the Mann or Mahle filters which are known good - can't
do
> anything but help.
>
> Make sure both the switch and the connection is secure.
Zoltan said:
> It sounds like the oil pressure sensor is getting bad.
The connection seems OK. Maybe the high-pressure sensor's bad. (The
low-pressure sensor doesn't seem to play a role in this.) Based on
Dennis's theory, it could simply be erroneously signaling "low pressure"
when the pressure isn't really too low.
I think I'll try replacing the filter with Mann or Mahle at my next oil
change, and see if that makes a difference. It it doesn't, I'll replace
the high-pressure sensor switch (assuming I can get to it).
After that... I don't know. Maybe some 75W200 oil or something.
- Steven Sittser
-----Original Message-----
From: Steven Sittser <ssittservl@aol.com>
To: vanagon <vanagon@gerry.vanagon.com>
Sent: Wed, Apr 4, 2012 7:13 pm
Subject: Oil pressure light and buzzer
My oil pressure light and buzzer are coming on. I know, I know, that
happens on lots of Vanagons, but, after searching through the mailing
list, reading the description of the system at GoWesty
(http://www.gowesty.com/library_article.php?id=810), and looking
elsewhere, I haven't quite found a match for my symptoms.
I have an '88 Westfaila, with 20W50 oil that I put in in November, and
some filter they had in a package deal sale at AutoZone - might have be
an STP. My oil level is fine.
The buzzer comes on and the light starts flashing only under the
following conditions:
(1) It's hot outside, or at least pretty warm, and
(2) I've been driving at highway speeds for at least
about 10 minutes, and
(3) I decelerate (usually getting off the highway), and the
engine RPM's are below about 2000.
If I raise the RPM's above about 2000, the light and buzzer go off,
then come on again if the RPM's drop back down again. This goes on for
5 or 10 minutes, after which it will usually get tired of me ignoring
it and the buzzer and light will go off.
The strange part is, the GoWesty description, and other, similar
descriptions, say that the buzzer can only come on ABOVE about 2000
RPM. Mine only comes on only BELOW about 2000 RPM.
It may or may not be significant that, about 8 years ago, the van was
in a serious front-end accident. The shop that did the repairs was
less than thorough, and I still occasionally discover things that were
mis-wired or installed poorly. I've also had some major engine work
done in the last year or so by a shop that has turned out to be less
than competent (but what they lack in competence they make up for in
high prices), so there is at least some possibility of miswiring (or
other issues) there, too.
So: any ideas what's up?
I've read that many people feel that using anything other than Mann or
Mahle filters can cause the buzzer and light, but I've read others that
think that using them is just masking a problem that has some other
cause. Still, maybe I should just change the oil and try a German
filter.
I could try replacing the two oil pressure switches. From what I've
read this sounds fairly difficult (or expensive, if I have a shop do
it) for something that may or may not be the problem, but perhaps
that's the way to go.
I'm sort of thinking (but not at all sure) that I don't have a real oil
pressure problem, since this has been going on for a while, and the
engine hasn't exploded yet.
And in any case, there's the oddity of my light and buzzer only coming
on below 2000 RPM, when all the literature I can find says the buzzer
only comes on above 2000 RPM.
I've had the problem occasionally in the past, but I didn't pay enough
attention to know if the symptoms were identical. At least once it was
a loose wire on one of the pressure sensors, but I don't think that's
the case this time - the behavior seems too predictable, and not random
enough for a loose wire. I've used mostly Fram, Mann, and Mahle
filters in the past, but occasionally something else, usually (as far
as I remember) without trouble.
Thank you for any advice!
- Steven Sittser