87 5KCSTQ How to shorten afterrun time/battery drain

[Lee Levitt]

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