Bernstein, Jeff (PSC-Akron)
Jeff.Bernstein at pneumaticscale.com
Wed Oct 4 07:53:13 EDT 2006
I have personally experienced four turbos fail and every time the problem was fixed by replacing the turbo. All of the turbos that I had fail started smoking on long periods of idling. I am not exactly sure why and it really doesn't matter at this point. All the turbos that I had fail were early technology and they didn't have the water cooling jackets which add an incredible amount of life to a turbo.
You can easily remove the hose on the intake side of the turbo and check for oil. I would suggest checking it prior to idling and then after idling to see if you see any additional oil residue. It could be leaking on the exhaust side and this is harder to observe.
They amount of smoke that you describe and the length of time it takes to clear after idling seems like too much to be just valve seals. If your oil seals are this bad then the long deceleration technique that I described should give a huge cloud of smoke behind you. Try pulling the hose on the turbo to see if there is a lot of oil in it and this may answer the question of which part are failing.
From: Derek Pulvino [mailto:dbpulvino at hotmail.com]
Sent: Tuesday, October 03, 2006 8:13 PM
To: b.benz at charter.net; Bernstein, Jeff (PSC-Akron)
Cc: 200q20v at audifans.com
Subject: Re: Burning Oil???
Reading this, I guess you don't necessarily buy off on the turbo culpability
theory? Jeff, were you able to solve your problem by replacing/rebuilding
the 924 turbo?
> > Derek,
> > The oil burning that you are describing sounds like a turbo going bad to
> > If, as was mentioned in an earlier post, you have smoke on long
> > 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
> > of smoke on acceleration after idling sounds like too much smoke for a
> > 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
> > Turbo and my Audi 5000CS Turbo when the turbo seals were failing.
> > when the car idled for any length of time with the oil pressure being
> > it would allow a lot of oil past the seals. As soon as you accelerate
> > burn the excess oil out of the turbo at a fast rate which makes a huge
> > of smoke. Under normal running conditions the oil pressure was
> > 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
>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
> > Jeff Bernstein
> > Canton, Oh
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