Date:         Tue, 5 May 1998 09:14:43 -0400
Reply-To:     Lawrence Johnson <ljohnson@HALHINET.ON.CA>
Sender:       Vanagon Mailing List <Vanagon@vanagon.com>
From:         Lawrence Johnson <ljohnson@HALHINET.ON.CA>
Subject:      Re: the cat did it (solved)
Comments: To: SyncroHead <SyncroHead@aol.com>,
          Multiple recipients of list <vanagon@vanagon.com>
Content-Type: text/plain; charset=us-ascii

Jim Davis wrote:

> > 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.   ??
>
> Except that BOTH oil pressure switches indicate when oil pressure is too LOW.

 The buzzer sounded at >2000 rpm so I assume that the higher pressure sensor was
responsible. The oil leak was at the lower pressure sensor (for <2000 rpm). The
leaking sensor was replaced at the same time as the catalytic converter (the
blockage) was replaced. The engine ran smoothly but on a road test, the oil
buzzer/light sounded/blinked. This higher pressure sensor for >2000 rpm was then
replaced and the false buzzer/light did not repeat. Maybe the oil pressure sensor
was damaged by the too high oil pressure. I like Joel Walker's explanation of too
oil pressure because it predicted symptoms which the van exhibited but which I had
not included in my original description like my oil leak and my finding gas in the
oil. Somehow a Joel's explanation has a ring of truth.
Larry

> One is used at low engine speeds and has a lower oil pressure setting and one
> is used at higher engine speeds and has a higher pressure setting.  Both
> indicate when oil pressure is too LOW though.  I think that perhaps the gases
> in the crankcase and lack of proper "breathing" may have heated up the oil and
> caused the pressure to drop too low.
>
> Regards,
> Jim Davis

  This is exactly what most on the List have told me and what I thought at first.
Because my oil pressure sender was found to be faulty, I can't be sure what was
happening.

Larry