1982 Diesel 245 GL Temp Gauge High, Doesn't Seem to Overheat

[adje]

I have an '82 diesel wagon with a 6 cylinder Volkswagen engine. Though there are no signs the car is actually overheating, even if I just run it parked for 10 minutes the temperature gauge is nearly in the red. The water pump, thermostat, and radiator all seem to be working fine.
I'd like to test the temp. sensor in the engine block to see if it's just giving inaccurate readings...does anyone know how to do this, or have another suggestion as to what might be wrong?

Thanks!

[93Regina]

'82 diesel wagon...temperature gauge is nearly in the red.

Verify with Temperature Gun around thermostat.

At block sender unit, make sure wire has a good contact with temp-sender, and terminals are clean. Also, check to see if wire has been touching block/etc...is it bare somewhere...

Without a diagram, there is not much to say; I assume it is a single wire setup.