overheating

[Zsolt Kovacs <zsolt@telusplanet.net>]

My warning guage in my 86 5ktq has been going off for a while (no time
having it looked at) but I wasn't overly concerned 'cause my temp guage
was fine, however today in about 20 min. the temp guage went back and
forth between min. and max.  (50C-120C) temperatures about 3 times and
then decided to stay just below 120C. There seem to be enough coolant in
the system, and the fan didn't go off at all. The outside temp is about
-8C. I'm wondering if is the thermostat or the sensors, or perhaps
something else. I know my previous Audis used to run fairly hot, but not
like this, and only in hot wheather in heavy traffic.

Thanx
   Zsolt