Burning Oil???

[Bernie Benz]

> From: "Bernstein, Jeff \(PSC-Akron\)" <Jeff.Bernstein at pneumaticscale.com>
> Date: Tue, 3 Oct 2006 07:58:26 -0400
> To: "Derek Pulvino" <dbpulvino at hotmail.com>
> Cc: 200q20v at audifans.com
> Subject: Burning Oil???
> 
> Derek,
> 
> The oil burning that you are describing sounds like a turbo going bad to me.
> If, as was mentioned in an earlier post, you have smoke on long deceleration
> then I would suspect valve seals.   If you don't get smoking on long
> deceleration then it is most likely turbo seals starting to fail.  The amount
> of smoke on acceleration after idling sounds like too much smoke for a valve
> seal problem to me.
Could be, Jeff. If so, one would find the intake plumbing from turbo to
throttle body flooded with oil. An easy check Derek. This intake piping and
the IC will usually be lightly oil wetted inside, but not flooded.
> 
> The smoking on long idling is exactly what would happen on my Porsche 924
> Turbo and my Audi 5000CS Turbo when the turbo seals were failing.  Apparently
> when the car idled for any length of time with the oil pressure being very low
> it would allow a lot of oil past the seals.  As soon as you accelerate you
> burn the excess oil out of the turbo at a fast rate which makes a huge cloud
> of smoke.  Under normal running conditions the oil pressure was sufficient to
> keep the seals from leaking on the turbo.
Not the likely scenario, Jeff. There is lots of oil storage area from the
turbo to the TB from a leaking turbo, but nothing excepting the cylinder for
a valve stem seal leak to go. Turbo seals are labyrinth, not contact seals
and are on the drain sides of the bearing, not the pressure side. Their
leakage is not supply pressure dependant, but is primarily turbo bearing
wear dependant.

Bernie
> 
> Jeff Bernstein
> Canton, Oh