Date:         Wed, 23 Jun 2004 20:02:45 -0400
Reply-To:     The Bus Depot <vanagon@BUSDEPOT.COM>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         The Bus Depot <vanagon@BUSDEPOT.COM>
Subject:      Re: oil filter question
In-Reply-To:  <003401c459d8$a5b02910$34e45e44@noneq06xyh6uat>
Content-Type: text/plain; charset="us-ascii"

>>  The Golf/Jetta has an oil filter bypass in the engine, the Vanagon
>> engine does not. This is the difference between the two filters.

> Air Cooled Vanagon engines have a bypass and the WBX have
> this valve too. I can prove it with pictures if it requies that.



Here is the difference, quoted verbatim from Mahle/Germany's response to
these questions (and taken from the list archives)...

"The main difference between OC 108 and OC 47 is inside these filters.
OC 108 has an anti-dran valve at the filter, OC 47 not. When you use OC
47 for your car (VW Tranporter/Vanagon) than you can get problems when
you start your car. The motor is at this time alwys to long without oil.
OC 108 have also a better paper quality than OC 47, and the pressure
bypass is different. Please use for your car OC 108, to get no damage at
your car or motor."

So, the differences are threefold...

1) existence of anti-drain valve (not found on the OEM Golf filter)
2) design of bypass (differs between the two models)
3) quality of paper filter element (better on the Vanagon filter)


Below are additional comments regarding Mahle's response, provided by
the listmember who had queried Mahle about this in the first place. The
only difference is that his reference to Mann being the same as Bosch
does not apply to the U.S. market, where Bosch is actually a Champion
filter......


"Now for some background.  The e-mail is verbetim -spelling error and
bad english et al.  Obviously, Sandra's English is not the best, but you
can all undertand what she is trying to say. (Besides, who am I to
criticize somebody's English!!)  The OEM filters on VW's are either
Mann/Bosch or Mahle/Knecht.  VW Dealers usually carry Mann (same as
Bosch) while most foreign autoparts stores carry Knecht (same as Mahle)
if you ask for OEM filters.  I wrote to both Mann/Bosch and Mahle/Knecht
but only Mahl/Knecht anwered my inquiry. OC108 is the filter listed for
the Vanagon and OC47 is listed for the Rabbit/Golf.

Here's why the difference is important for all of us Vanagon owners.
The by-pass valve and the "anti-drain" or anti-flow back valve is
critical to our engine.

1. The by-pass valve. You all know that if the filter is clogged, and
pressure built up, the by-pass valve opens up to let oil through.  The
idea being that dirty oil is better than no oil.  However, the other
reason for the pressure by-pass is even more important. During a cold
start, when the temp is low and the oil is thick, it will not transverse
the filter elements very much..which builds up pressure. .and enough so
that the by-pass valve opens up.  If it fails to do so, your engile
bearing will be starve for oil until the oil warms up enough to go
through the filter.  The by-pass pressure for the Rabbit/Golf filter is
set differently than for the one in the Vanagon.  (The Vanagon is lower)

2. Anti-Drain/Anti-backflow valve.  Here is the CRITICAL difference. The
Rabbit/Golf oil filter do NOT have anti-drain valve.  Neither does most
other 3rd party vendors like FRAM, AC Delco etc. Filters that are meant
to be mounted on it side or at an angle will have the anti-drain valve.
The Rabbit/Golf filter is mount bottom down.  The Vanagon filter is
tilted on it side.  When you leave your engine off over night, filters
mounted on it's side or tilted will drain all or most of the oil back to
the sump unless there is an anti-drain valve to keep the oil in the
filter. Back flow will put dirt particles back in the sump but MORE
IMPORTANTLY, when you startup in the morning your Vanagon will be
starved of oil until the pump refills the filter canister.  This is why
some of you hear banging noise in your engine for a few minutes after
you startup in the mornings... YOU ARE USING THE WRONG FILTER!  The
anti-drain valve shuts off reverse flow of oil back to the sump, thus
keeping oil in the filter and all the upper oil passage way.  In that
way, there is oil pressure in the bearings as soon as you restart your
engine in the morning. And if the pressure by-pass valve is working, you
will have instantaneous oil pressure in your critical engine parts.

Now, some models of FRAM have anti-drain back valve.. but it is just a
little plastic flap over the exit portal.  The ones in the Mahle/Knecht
filter is a spring loaded metal valve.  Take a pick of what filters you
want to use in your beloved Vanagons, but make sure it as anti-drain
back valve... and the by-pass pressure valve is set correctly for the
vanagon engine.

Anyway, folks.. here it is.. do not use Rabbit/Golf filters in your
vanagons. You can use Vanagon oil filters in your Rabbit/Golf.

Now, I am sure some of you have been using Rabbit/Golf oil filters in
your Vanagons and it is still alive an well.. Dumb luck never hurts when
owning a Vanagon!

- Yau-Man Chan "


- Ron Salmon
  The Bus Depot, Inc.
  www.busdepot.com
  (215)  234-VWVW

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