Greetings to all,

After one week of not driving the car, my 1980 DL temp went up to top of green area and hung there. Normally the needle sits in the dead center of the gauge. I changed the thermostat (which was over due) and the water pump (which had developed a small leak (after 25,000 miles). Same temp indications persist. Temp will drop slightly after opening heater (and windows).

I remember back in '85 the sensor failed and gave erroneous red line readings, but don't recall how to tell if the sensor is bad. Can anyone help?

Chuck2

Hi Chuck,
The sensor works with a negative temperature coefficient.
So for a basic test of the system you can short the wire to ground and you should
have the gauge go full hot. If you disconnect the wire and keep it open from
ground the gauge will read full cold. If the gauge does all this then it's probably OK. However make sure you check the wiring for decay. I forget the
ohms but you can measure the sensor with the engine cold then warm the motor up
and check the sensor again. I know the ohms go down but I forget how much. It's
probably in a Haynes or Bentley. The sensor is about halfway back from the front
of the motor under the intake manifold. I believe it's a one yellow wire spade
connector on the head. Hope this helps some.

Dave 82 242ti 277k mi.

Dave,

Just the info I was looking for. Thanks. I had also taken out the radiator to wash of the fins & remove any debris. Inside looks a little crummy (after all, its the original rad)and I haven't yet done the flush but I plan to tonite. Will let you know what I find.

Chuck2