87 5KCSTQ How to shorten afterrun time/battery drain

[Paul Meyers]

So you're saying that extra cooling in hot weather just before shut-down is
a bad thing? And that the only way good things happen is with the automatic
systems Audi built in? In that case none of us would chip our cars or
install more powerful lights or do suspension or brake mods ore anything.

The afterrun system is there to protect against turbo coking (cooking the
oil) due to extreme heat after vigorous runs in hot weather. You'll notice
that it almost never runs in cooler weather. Are you saying it SHOULD run
every time, regardless of how hot the engine is? All I'm doing is,
hopefully, removing the need for the system to run, or run so long. My
afterrun system still runs fine and occasionally comes on even now. If
you've never seen the system run for more than 5 minutes, you don't live at
high altitude in the desert, or drive the car really vigorously before
shut-down.

On the other hand, it's a free country. Everyone I've talked to about this
mod (like changing out the plastic heater control valve), excepting
yourself, has decided to do it. But you are perfectly free to not do it.

As always, YMMV.

Paul Meyers
-----Original Message-----
From: Lee Levitt [mailto:lee at wheelman.com]
Sent: Thursday, June 06, 2002 4:32 AM
To: quattro at audifans.com
Subject: RE: 87 5KCSTQ How to shorten afterrun time/battery drain

Paul Meyers <paul.meyers at citrix.com> writes:

> This is an idea I got from a lister several years ago and finally
> got around to implementing. I'm so happy with it that I wanted to repost
it to a
> (potentially) new crop of Audi fans.
>
> The typical application is a commute home on the freeway on a hot day with
> the AC on full. On exiting to take city streets (read stop and go traffic)
> to get home, the temperature rises dramatically. You pull in the driveway
> and the afterrun system comes on and stays on for what seems like a half
> hour, depleting battery charge and maybe even requiring a preventative
> battery charging once a week to keep the charge up, especially if you do a
> lot of short trips in hot weather.
>
> Solution: install a manual switch on the dashboard to turn the cooling fan
> to "hurricaine mode" when exiting the freeway, so that, by the
> time you get home, the engine is cooled down to the normal temperature
range.
>

This seems like a bad idea to me. Audi designed the afterrun pump and fan to
cool the engine down after shutoff, to keep the engine from heatsoaking.
Running the cooling fan prior to shutdown will not keep this from happening.

We had a problem with our '90 200T, which ran the afterrun pump and fan
after *every* run, rather than only after the engine got sufficiently warm.
After a week of short trips, the battery would be exhausted as it wouldn't
get enough time to recharge on the short trips.

We ended up replacing a thermal switch that was defective and everything was
fine.

The system is designed to run about 5 minutes, when necessary. This is not a
big deal for a battery in good condition, and I'd certainly rather replace a
battery every so often rather than a turbo or a block or a head.

IMCO, you're just asking for trouble with this mod.

Lee
'95.5 S6 avant
'96 A6 quattro avant