FW: 200 TQ Hissssssssss....

[Peter Berrevoets]

missed the list...

If the michelin man hose is ok, the most likely culprit is your turbo high
pressure side to intercooler intake hose, likely right at or almost under,
the clamp holding it to the intercooler intake port.

The earlier cars used a singal piece 'U' shaped hose that is the ideal
replacement for this pirece. The MC2 which you may have has a three piece
unit with a noise suppressing foam insert. This ended up inside my
intercooler btw.

You will have to take the hose off to check it because it will leak only
under boost, and will not leave any sign of a leak otherwise. A visual
inspection is awkward because you can't really get a good angle to look at
it.

Mine had this problem and took me quite a few weeks to finally track it
down. I'd even been told to not bother looking there because 'that hose
never goes...' True - on the earlier cars.

HTH & GL

Peter Berrevoets
1990 200TQ
Toronto, Canada
http://frontpage.home.net/pjberr/


-----Original Message-----
From: quattro-admin at audifans.com [mailto:quattro-admin at audifans.com]On
Behalf Of Kurt Wesseling
Sent: Sunday, July 01, 2001 11:13 PM
To: quattro at audifans.com
Subject: 200 TQ Hissssssssss....


Guys:

Remember me?  8-]  Been lurking for the past 8 months or so.

Patient is my 89 200 TQ with 193,000 miles on the clock, 1.8 bar WG spring,
no chip.

Last week I noticed a loud hiss from under the hood at 1.0 bar and above.
The higher the boost, the louder the hissing. Thinking it was something in
the turbo circuit, I took it in to my mech for a look.  We found several
broken EM studs and that the EM was cracked.  Not really any surprises
there.  Seemed reasonable to think that would cause the hissing.  I had him
replace the studs and weld up the cracks since a new manifold is around
$900.00 USD. Picked the car up yesterday and it is still hissing.  The
$720.00 EM repair changed nothing--made the car a bit quieter, I suppose.

Symptoms are similar to those many of us have seen with a split IC
hose--except the hose is ok.  If I keep pushing beyond 1.1 bar, I get black
smoke from the exhaust and the engine begins to stumble.  Sparks plugs,
W7DTC's, show no significant oily deposits and are light gray at the
electrodes. When I let off the accelerator the hiss continues for about two
seconds and slowly dies off, leading me to believe that some component is
being pressurized and the air is escaping from a small hole somewhere.

So what do you think--small hole in the intercooler?  The ends don't appear
to be loose.  Perforated WG diaphragm? Some gasket I don't know about?

Opinions very welcome!

Thanks,

--Kurt

1989 Audio 200 TQ, 1.8 bar ...usually!