Date: Sun, 12 Dec 2010 10:34:10 -0500
Reply-To: Dennis Haynes <d23haynes57@HOTMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Dennis Haynes <d23haynes57@HOTMAIL.COM>
Subject: Re: Oil pressure light comes on after about 7 minutes.
In-Reply-To: <AANLkTimShb66i6S-Ni2McsbMiPQ8_q3VPYgYyqu50Cea@mail.gmail.com>
Content-Type: text/plain; charset="US-ASCII"
We need to kill this myth about Mann or Mahle filters being a fix for the
oil pressure buzzer syndrome. The oil buzzer is operated by the high (.8
bar/11.3 psi) switch. This switch closes when oil pressure is sufficient.
If the switch is not closed when the engine is above ~2,000 rpm you will get
the light and buzzer. The light/buzzer will remain on until this switch
closes or you switch off the ignition. Now since you are OK at start up
your wiring and buzzer board are most likely good. So what happens after few
minutes is that your engine is having trouble maintaining oil pressure or
you have the wrong switch in place. As for the filter, the high pressure
switch is between the pump and filter, not after. So the only thing a filter
can do to stop the buzzer is to be more restrictive which will actually
reduce flow to the engine. Now here are the things to check/test:
Do you have the correct switch installed? Most parts books and ETKA are
confusing here. Most water cooled VW use a 1.8 bar switch. This just won't
work. Easy check! If your switch is white it is the wrong one.
Oil viscosity-level. Well you say 20w-50, that is fine. Did you have the
temptation to overfill? The top mark on the dipstick is the full mark. It
is the maximum, do exceed no matter what mark and for the Waterboxer it is
really overfilled. Oil change with filter, 4.5 quarts is plenty.
Is the engine loaded with sludge and other deposits? These can get sucked
down and into the suction inlet screen. Unfortunately for Waterboxer this
usually means teardown.
A healthy engine should be able to get close to 10 psi/1,000 rpm. There
will be times when it will not. But if you can't maintain 11.3 at 2000 you
have a problem. Test the oil pressure with a gauge.
Dennis
-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
Roland
Sent: Saturday, December 11, 2010 4:32 PM
To: vanagon@GERRY.VANAGON.COM
Subject: Re: Oil pressure light comes on after about 7 minutes.
Well, this is follow up from my post a few days ago (below).
So, last weekend I drained and refilled with 20W50. I thought all was going
to be good, went a good long distance on the test drive (to where my son is
working at the christmas tree "store" in the mall parking lot). All was
well, but then suddenly on the way home the oil light/buzzer came on again.
But this time it took much longer, maybe 10-15 minutes. Once it was on, it
behaved like before, kind of on-and-off depending on driving conditions.
So I got a Mann filter, haven't installed it yet.
And then an urgent trip came up today, we have to get a tree, now! "Ok
honey, I'll risk it with the van". (What we do for our babes is just
amazing isn't it.) So I just took the exact same trip as I mentioned above
to the Xmas tree store at the mall and back again. No oil light / buzzer at
all. Van just sat in the driveway between these 2 trips, maybe the oil
rested and matured and is now ready to behave. Kinda like putting your kid
in "timeout".
So this is getting puzzling. I will still put the Mann filter on today and
then more extensive test drives tomorrow.
Roland
On Thu, Dec 2, 2010 at 7:21 PM, John Rodgers <inua@charter.net> wrote:
> I would drain the oil, install a Mahle or Mann oil filter, refill
> with a good brand of 20W50 or 15W50 Mobil One or good diesel 15W40. If
> that doesn't fix it, you may have an internal problem, but if things
> were good before the oil change, this should probably fix it.
>
> John Rodgers
> Clayartist and Moldmaker
> 88'GL VW Bus Driver
> Chelsea, ALHttp://www.moldhaus.com
>
>
> On 12/2/2010 6:48 PM, Roland wrote:
>
> Hello folks,
>
> Very odd, the oil pressure light comes on after about 7 minutes of
driving.
> 1989, 2.1 WBX. It happens every time. If I let it sit, and get
> half-way cool, then it takes about 2-3 minutes for the pressure
> light/buzzer to come on. I think the timing is associated with the
> oil warming up. This has never happened before. I recently did an
> oil change, so maybe... And I have been doing some studying in the
> archives. So, I had bought one of those package deals at Autozone,
> you know for about $0.43 you get 5 quarts of oil and a filter.
>
> So, first, I took some oil out, it was near the high mark (in the past
> I have suffered the oil pressure light on long uphills, so I am
> familiar with this problem). The oil level is now close to the
> minimum mark. Problem remained.
>
> So it was a Bosch filter, and in the archives this oil filter is
> questionable. So today I replaced it with a Napa Gold, which is
> really a Wix, which was recommended, and the problem remains.
>
> The oil is still golden in color and clear,no sign of chocolate mousse
> or contamination.
>
> When I go downhill, at idle in neutral, the light/buzzer go out after
> about
> 7-10 seconds.
>
> The next step I am considering is to get some different oil. I know I
> am being a bad vanagon owner, but I can't even recall what oil or
> weight I used, pretty sure it was 40W or close to that. Probably
> Castrol or Pennzoil, just can't recall. So I am thinking of putting some
20W-50 in.
> Am in San Diego, really never drive it below 40 degrees, but this is
> not a high temp / high stress problem, we are in the 50s-60s each day.
>
> I think I have a "frothing oil" problem of some type. Another post
> said that "Castrol GTX 20w-50 is only $13 for 5 quarts at Wally
> World", maybe not anymore, but I haven't been there is a while.
>
> Any comments? Thank you!
>
> Roland
>
>
>
>
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