flaky temp gauge?

[Dave Hord]

Hey all,

Forgive me...but it's been 8mo. since I drove the audi regularly.  10 months
ago I put a new temp sensor in the car, as well as thermostat, coolant flush,
water pump and timing belt.  Temperature sensor was gone for about 3 months
before that.

So, basically...it's been a year since I remember SEEING the temp needle...yet
alone what it should be at!

Car: 89 90 quattro.

Problem?: Driving to work in 0 deg Celcius weather, I'm only getting just about
50 deg C on the temp gauge. Drive is 45min, all highway speeds.  Gauge RARELY
got above the first three bars when I've been driving the car the last few days
(all 0-10 deg C).  During one afternoon (14 deg C) of stop and go traffic I
actually saw 90deg on the temperature gauge!

Car physically _seems_ to warm up.  I can tell the performance difference
between cold and hot. Drives like it should.  But as I recall, engines are
designed to run just under the boiling temp of water...say 85-90 deg C...right??

The question is...do I have a problem, or just a flaky gauge/sender?? How would
I test this.  I know I can test the gauge by grounding it out for a while
(should go right to max) But how would I test the sender to see if it's okay?
Short of testing the resistance, comparing that to spec...and putting a
thermeter in the coolant to see that it's correct???

Could my new thermostat also be at fault? Stuck open/closed?

I get GREAT heat out of the heater though, so surely the car isn't running
_too_ cold.  Mind you, I say great heat for my car...there's no insulation, no
heater ducts...it just blasts out at your feet or the windshield...but it does
_feel_ just as good as 5 years ago!

Any ideas would be appreciated...

-Dave
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89 90q  300km+ Rally Conversion...
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