If you have a Haynes manual, there's a test procedure described for testing the gauge so you don't try to fix something that isn't broken. atWith the engine cold, turn the ignition to the ON position without starting the engine. The gauge should sit on 100 degrees. If not, then either the gauge or sending unit is incorrect. If you have a ohmeter you can check the gauge sending unit to see if it's faulty. We have a thread for GM temp sensors in our tech section. If you have a reasonable idea of what the ambient temperature is, you can determine if the sending unit is correct. Just do a search for CHART to find it.
