Date:         Sun, 3 May 1998 17:20:57 -0400
Reply-To:     Lawrence Johnson <ljohnson@HALHINET.ON.CA>
Sender:       Vanagon Mailing List <Vanagon@vanagon.com>
From:         Lawrence Johnson <ljohnson@HALHINET.ON.CA>
Subject:      the cat did it (solved)
Comments: To: Multiple recipients of list <vanagon@vanagon.com>
Content-Type: text/plain; charset=us-ascii

Power to the List. Where two VW mechanics failed, Joel Walker succeeded.
Here is a copy of Joel's analysis and my reply:
~~~~~~~~~~~~~~ C O P Y ~~~~~~~~~~~~~~~~~~~~~
Joel, I think you have the answer to my question:

<<Question: what has low oil pressure got to do with a plugged exhaust?
We
were told by two reputable VW mechanics that this was not their first
experience of low oil pressure in conjunction with a plugged cat but
neither of them could explain the causal relationship. Can you?>>

Joel Walker wrote:

> you may be making the wrong assumption: what if the light and buzzer
> came on because of HIGH oil pressure?? there are TWO sensors. if the
> cat is plugged, then the exhaust is restricted, so the combustion
gases
> can't get out that way, so they'd likely blow past the rings (much
more
> than normal) ... pressurizing the crankcase more than usual. that's
the
> only thing i can think of. but it should have popped the dipstick off
> or blown oil out somewhere.   ??

Your prediction is correct: yes, we were blowing oil out past the
pressure
switch. Your description also explains why we found gasoline pollution
in
the oil.

Thanks again Joel,
Larry