Jumpy Temp Gauge
 

My engine temp gauge will typically run a little over the midrange temperature mark while driving around town. It goes to the third temp mark and stops, typically. However, it will also occasionally bounce around wildly from max temp back to mid range rapidly and then settle down. It is simply a bad temp switch? Should I just replace the temp switch and the thermostat?

On an 83, this can be caused by poor grounding at the following locations: under the dash, between the engine and tub, between the battery and the tub, between the battery and the engine, or a loose connector at the sending unit.

Solution is to take apart grounds, clean them with a wire brush and small file, and reassemble with conductive grease. If you are serious about driving the car for a long time, also consider refreshing the battery cables and alternator harness.

Rasta, thanks, I will check them all. JBC

I removed the electrical clamp to the engine temperature sensor and found a lot of white corrosion under the clamp. So, I wired brushed it clean, applied conductive grease and put it back on. It seems to work.