RE: What is the best Thermostat temp?

["Buchholz, Steven" <Steven.Buchholz@kla-tencor.com>]

> > This is my 4th Audi (this time an 86 5k CD tq) but they all did that.
> The
> > temperature ranged between about 80C-110C depending on outside
> temperature, and
> > driving conditions. I am also curious to get an answer from someone with
> more
> > experience why that is. I had an old MB 200. Once it warmed up the temp
> guage
> > didn't move. Why does the Audi's?
> 
> 	I agree.  My old Jeep Cherokee, our old Van, my 65' Buick, even
> our old Fuego Turbo stayed the same.  Yet every older Audi I know of does
> this flucuation thing.  That is a good question why they do this.  I know
> my friends VW Jetta does this too.  I wonder if the way the thermostat
> works just seems to be all or nothing than other cars.  I really have no
> idea though.  L8R
> 
... I'm not familiar with the Fuego, but I'm pretty sure that all of the
other cars use some sort of radiator cooling fan that is attached to the
engine to ensure that there is air flowing through the rad when you aren't
moving very fast.  This would be a bit difficult on most of the Audi's I'm
familiar with, as the radiator is mounted in line with cylinder #1 ... :)
The reason you see the temp fluctuation on the Audis is that when you are
travelling at slow speed the water temp will increase until it reaches the
temperature at which the rad fan turns on ... at which point the airflow
will be increased and the temp will come back down.  

The V8q has a rad cooling fan attached to the front of the engine as well as
an electrically operated one ... although I still see some variation in
temperature, I must say it is nice not to see the needle hovering by the red
mark ...

If this bothers you, you can always rig an auxiliary switch to allow you to
turn on the fan when you feel it is appropriate ... I almost installed this
mod on my old Fox ... but it would have required adding wiring all the way
out to the fan as I didn't have A/C ...

HTH!
Steve Buchholz
San Jose, CA (USA)