[Biturbos4] After-run thermoswitch modification

Brandon Rogers brogers at terrix.com
Fri Nov 16 08:04:04 PST 2007

Very Cool - Thanks Ti-
I agree with your rational - I'll check this out.

Thanks again-


-----Original Message-----
From: biturbos4-bounces at diablo.audifans.com
[mailto:biturbos4-bounces at diablo.audifans.com] On Behalf Of Ti Kan
Sent: Friday, November 16, 2007 12:20 AM
To: biturbos4 at audifans.com
Subject: [Biturbos4] After-run thermoswitch modification

Hi all,

I replaced my S4's after-run system thermoswitch today with a lower temp
unit as described in this Audiworld article:

The original switch (357 919 369F) operates at 112 deg.C whereas the
replacement (021 919 369) closes at 93 deg.C and opens at 88 deg.C.
Installation is basically as described in the article, except that the
electrical connector retaining wire does not need to be removed.  You
just squeeze it inward and the connector should pull right out.  The old
switch was stubborn to come out, and the tight confines around it makes
it difficult to get a good grip with pliers.  But I used a vice grip and
it worked like a charm.

After a long drive back from a dinner appointment, I pulled
in the garage and shut off the engine.  Lo and behold, the after-run
system activated.  The auxiliary radiator fan and the reverse coolant
pump were whirring, which I had never heard before in the 8 years that
I'd owned this car.  It ran for approximately the full 10 minutes before
shutting off.

I think this is a worthy modification, and should help extend the
longevity of the turbos.  Not only does it circulate coolant through the
system (including the turbos), the fan also forces some airflow through
the engine bay to reduce heat-soak.

Just thought I'd share.


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