[s-cars] ANN with major oil leak

[Paul Gailus]

I agree with Pizzo that it could very well be the PCV.
The PCV valve is connected to the bottom of the intake manifold.
Unlike a PCV valve in a normally aspirated car, this valve needs
to close completely to prevent reverse flow from the intake manifold
into the crankcase under boost.

The larger diaphragm valve at the back of the engine is connected
beween the crankcase and the turbo intake boot (through a pipe inside
the valve cover). As far as I can remember from SJM and other sources,
when the pressure at the turbo intake gets below a certain point relative
to the crankcase pressure, then the valve closes down to a smaller orifice.
This keeps from pumping down the crankcase unnecessarily when
the turbo is boosting. This will also limit the amount of relatively
inert crankcase combustion gasses that get into the turbo and engine
when first on boost.

Are you sure that the oil is coming out of the crankcase breather?
I had a big oil leak from the oil pressure switch that got all over the
driver's side of the engine.

 Paul

----- Original Message -----
From: Joe Pizzimenti <joe.pizzimenti at gmail.com>
To: Lino M. Valadas <l.valadas at rogers.com>
Cc: <sos-cars at yahoogroups.com>; s-car-list <s-car-list at www.audifans.com>
Sent: Sunday, October 24, 2004 10:25 PM
Subject: Re: [s-cars] ANN with major oil leak


> Lino,
> That should only be a one way valve (crankcase vent to intake
> manifold, not the other way around) or there wouldn't be a valve
> there.
>
> Just went through this on the Evo.  When the PCV diaphragm tears,
> instead of the crankcase pressure going to the intake manifold, all
> 26psi of RS2 goodness (in your case) goes through that valve, into the
> crankcase and not being content to stop there, it follows the path of
> least resistance (hopefully the dipstick tube).
>
> Replace PCV, problem solved.
>
> Joe, no more Evo oil fountain, Pizzo
>
>
> On Sun, 24 Oct 2004 22:15:06 -0400, Lino M. Valadas
> <l.valadas at rogers.com> wrote:
> > After a great day at Mosport Ontario today, I drove home with hardly any
oil
> > left in the crankcase. Of course I did not know it at the time, but
decided
> > to check my oil level on I got home and that's when I found out.
> >
> > Futher investigation revealed a major oil leak from the crankcase
> > ventilation plumbing.  The drivers side (North American car) of the
engine
> > and surounding areas were completely soaked and driping with fresh Mobil
1.
> > Has anybode experience this?  Are my compressing rings going?  I had
done a
> > compression test recently on the car (93 S4 with 153K km) and all
cylinders
> > were good at 150 lbs/sq".
> >
> > Also there is  some sort of valve between the crankcase and the head in
the
> > vent pipe.  Does anybody know what its function is? I checked it and it
> > allows air to pass both ways.  Should it?   I have the Bentleys but
there is
> > no description nor reference to the crankcase ventilation system.
> >
> > Any info would be appreciated.
> >
> > BTW the car performed flawlessly at the track.  The BIRA system 3 was
> > awesome.  I did not let the 20vt crowd down.
> >
> > Cheers
> >
> > Lino
> >
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