Can anyone tell me my next step? '82 coll ed. water temp gauge moves past red area (260) when car is 1st started. Replaced sending unit already. Someone said,,,bad ground or gauge itself....any ideas? Thanks in advance.

 

Since you have already replaced the sending unit I would check the ground next. This series of vettes have an embedded wiring type board that has to make contact with gauges and ground. This could be the problem and then again t could be a bad gauge. Be cautious when you remove the instrument to check the gauge.

 

Hi my 1 st vette, Welcome to the website, you'll meet a lot of great people here. gigabyte is correct Vettes have and need all the original ground wires.
Does the car overheat or do the guages just indicate that?
Since you replaced the sending unit lets assume that it works properly.
Before you change the guage, try your auto parts store and see if thay will use there portable mini thermometer for your car, do you have a working thermostat, how much milage is on your water pump? Was to rad ever boiled out, do you havs the correct pulleys. I hope this helps you get to the cause without buying everything new. Also rad hoses should by changed.PG