Date: Wed, 9 Dec 1998 12:03:19 -0800
Reply-To: YauMan Chan <YauMan@CCHEM.BERKELEY.EDU>
Sender: Vanagon Mailing List <vanagon@vanagon.com>
From: YauMan Chan <YauMan@CCHEM.BERKELEY.EDU>
Subject: IMPORTANT INFO on Oil Filter- Conundrum no more.
Content-Type: text/plain; charset=US-ASCII
Ok.. fellow Vanangonian.
Someone here a few weeks ago asked about using Rabbit/Golf oil filters in the Vanagon. This question has bugged me ever since I first got my vanagon and realized that some manufacturers list the same oil filter part number for the Rabbit/Golf as for the Vanagon whereas Mann/Bosch and Mahle/Knecht list different parts.
So, I decided to get the answer from the houses mouth and this is e-mail I got which I will share with you:
"Thank you for your interest in KNECHT products.
"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.
"If you have any questions, please do not hesitate to contact me.
"Kind regards
"Sandra Rieger
"1 VGP - Productmanagement
"e-mail: sandra_rieger
Now for some background. The e-mail is verbetim -spelling error and bad english et el. 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. Either 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 bottoms 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 starve 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. An 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
87 GL
