Re: Rad Fan Revelations

[Mitch Loescher <Loescher@tamu.edu>]

>Umm, hesitating to disagree with my esteemed Q-list members, but my (her) '84
>5kS has run it's rad fan (if it's too hot) after you shut it off ever since we
>got it in '87.  It's possible someone retro-fitted something into the car
>before we got our hands on it I guess, but I'd guess it was a stock feature...

I hope I'm not reiterating anything here (cuz I'm joining the thread late),
but on my '87 5000SQ, the afterrun fan is triggered by an engine compartment
temperature of 120F or higher.  The thermosensor is on a little bracket back
by the #5 fuel injector.

The relay (with electronics) that senses the temperature also has a timing
circuit that won't let it run more than 20 minutes.  It uses the low fan
setting.

This is to avoid heat damage and fuel boilover in the injectors.

When I shut my car off, sometimes it comes on right away, and sometimes the
lack of airflow and hot engine mean it has to heat up for a couple of
minutes before the fan comes on.

The manual sez it is standard starting right about my year and is a
recommended retrofit for older cars.

 - Mitch