Especially since that valve is a bypass valve not a holding valve.  Note its
position.  If the media becomes clogged the oil then pushes against the
valve with enough pressure to go around the media and back to the engine.
The only anti drain associated with a filter I have ever seen is one way
valves in external lines.  Also note the orientation of the filter and where
it is in the line of the engines oil system.
jimt

On 5/2/05 4:25, "Dennis Haynes" <dhaynes@OPTONLINE.NET> wrote:

> Non-sense and wives tales!
> 
> Dennis
> 
> 
> -----Original Message-----
> From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf
> Of tabe johnson
> Sent: Monday, May 02, 2005 12:47 AM
> To: vanagon@GERRY.VANAGON.COM
> Subject: Anti-Drain Back Valve in Oil Filters??
> 
> OK --- can someone please explain how and why
> the anti drain back valves in the Mahle and Mann
> filters work so much better at keeping lifters
> from clacking?
> 
> 

����������������������������������������
jimt
Planned insanity is best.
Remember that sanity is optional.
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