re. Vac Leak - WG hissing?

[Ben Swann]

Ameer,

Itsounds like you may have a leaking wastegate diaphragm - wastegate should not "hiss".  Try applying vacuum to the upper port  - wastegate should rise and fall with an audible "clunk" when vacuum is release.  Mouth suction should suffice.

It is normal for an aging turbo to leak a little through the seal causing a little puff upon startup.  I think yours may be beyond this.

The bright side - things are easier to take apart when everything has been done recently.

Ben

[Date: Mon, 25 Oct 2004 12:30:43 -0400
From: Ameer Antar <antar at comcast.net>
Subject: Vac Leak - WG hissing?
To: Quattro List <quattro at audifans.com>
Message-ID: <20041025163038.4EB983E186E at audifans.com>
Content-Type: text/plain; format=flowed; charset="iso-8859-1"

I have my motor running finally, but it looks like I have at least a couple of issues. When I started it up at first, it seemed like it was running to lean. I adjusted the idle mixture, but it sounds like there's a hissing coming from either the wastegate or the back of the manifold. The question is, does the WG supposedly make any hissing noise in normal operation? How about if the diaphragm is torn? I have to pinpoint where this is coming from, maybe by capping off the line to the WG. Anyone have any suggestions on pin-pointing a vac. leak back there???

My other issue is it looks like the turbo is leaking oil into the exhaust or something b/c it started to smoke a lot after running for a few minutes. It seems to come from the turbo, and it even looked like it was dripping out slightly near the exhaust turbine housing. Ah well, sucks for me, I have to pull it, fix it and put it back... I wish I could have figured that out before closing the motor up... cuz it's such a pain to pull the turbo. 

Enough complaing... I hope someone can give some advice, BTDT's regarding the WG failure modes and vac leak issues. Thanks.

-Ameer]