HELP! Temp gauge spiked off the scale...99 GTS

[George Murray]

I think cooling system is fine...no leaks anywhere, full of coolant, and fans cycle on/off. No indications of overheating...no engine light, no coolant smell from engine or exhaust.

Car has been in garage for past seven days. This problem showed up last night when I pulled it out to take it to the gas station.

Temperature gauge spikes immediately when key is turned to "on" position. Without even starting the engine. Car was parked overnight, engine cold this morning, and when I hit the key, it spiked...weird one.

I suspect sending unit or gauge issue. Does anyone have a suggestion for a test to determine the problem?

Thanks in advance, George

 

[Lee Dove]

George, It sounds like it's grounded.

Take the wire off the temp sending unit then turn on the key and see if the gauge is back down to 0 If it is replace the sending unit. If it is not back to 0 replace the gauge......