1998 a4 30v overheating

[urq]

... you might want to investigate to understand how the heater works on your
car too ... I suspect the A4 has a climate control system rather than a
simple heater valve control ... in climate controlled systems the heater
core is often running at full heat, with the computer directing air over or
around the heater core to set the air temperature.  

Unfortunately I'm not familiar with the radiator fan circuit on your car ...
but if you don't see the fan running when the A/C is on it is a pretty good
sign something is not functioning.  The first thing to look for is a fuse,
the fan draws a lot of current, so that fuse may be what is called a fusible
link, which is a metal strip mounted under the hood somewhere.  Fusible
links can fail from being in the underhood environment for a long time.
Since the fusible link has a high current battery connection it is often
under some sort of insulating cover.  Follow the big positive wire from the
fan motor ... chances are it will go directly to a fusible link if there is
one.  

You may have more than one thing wrong with your car ... and digging further
into what controls the radiator fan is likely to require a schematic or
service manual.  

Steve B
San Jose, CA (USA)

-----Original Message-----

I'd check out whatever sender tells your fan to turn on - in the cars 
I'm used to, it's usually in the bottom of the radiator.  With any luck, 
from that location you can "fool" the fan into running by simulating 
what the sender does when hot.

I don't know the A4 well enough to really tell you where to undo things 
to test them, but look at wherever the fan motor gets its power, see if 
you can undo it to test the fan with power & ground.

Schematics will be useful in this process.

Tony Escobedo wrote:
> Hello all,
> 
> A little frustrated here..  My car overheats and I'd rather it not. I
> put in a new radiator yesterday cause it blew up the last one. My
> cars heater when on HI  blows hot only when it wants to and the
> radiator fan doesn't spin when the car is warm nor when the AC is
> cranking..  The AC blows cold, but something amiss. Please help!!
> Anyone been here? Things to look for? Dead fan? Dead relay? Fuse?
> Thermostat seems intermittent cause of the sometimes heater working..
> TIA
> 
> Tony in Miami