RE: S4 Wastgate noise

["Mike " <JoMi@msn.com>]

Sounds to me like the turbo bypass valve is opening, dumping boost as it 
should. If the noise is new/getting louder, perhaps the bypass valve is 
opening sooner. I think the 92 S4 has enuf similarity to the 91 3B engine for 
the following. Check the hose that runs from the back of the Intake Manifold 
to the turbo bypass valve for leaks or being crimped where it comes out of the 
IM - there is a bracket there that the hose runs overs that is not the best 
design in the world allowing the hose to pinch. The cost of a new wastegate 
from the Dealer is ~$900. There are places that rebuild them for ~$300. 
Swapping a WG takes well under 1/2 hour - dealer labor is around 2 hrs as I 
recall. The WG is really very simple inside and not at all difficult to take 
apart.  The bottom seat should be floating. Mine with 75k miles had a worn 
valve guide and crudded up valve stem. I cleaned the crud off the stem and 
touched it up with some 400 grit and it moves much more freely. Could be the 
bypass valve is bad - Peter just replaced one for ~$45 as I recall. Are you 
still seeing full boost? Send me private Email if you want detailed 
instructions for pulling the WG - it's only 7 nuts to remove.

mike miller
91 200q

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From: 	owner-quattro@coimbra.ans.net on behalf of Tim Miller
Sent: 	Tuesday, November 19, 1996 8:51 PM
To: 	quattro@coimbra.ans.net
Subject: 	S4 Wastgate noise


I have a 92 S4 with 52k miles on it.  Lately there has been a noise coming
from the engine when I let off the gas pedal after hard acceleration.  Over
the past few thousand miles this noise has been getting louder and occuring
more often.  The dealer told me that it was coming from the wastgate and this
is normal.   I do not like the sound and I don't feel that it is normal. 
After the turbo winds up and I decrease power is when the noise occurs.  The
noise can best be described as a wheezing, discuss type sound.    Does anyone
have a similiar problem?  Is replacing the wastgate an expensive job?  Any
help is greatly appreciated.

Tim Miller
92 S4 TAP Chip