The low coolant level light in my wife's 96 Corsica came on yesterday. I checked the reservoir and added some antifreeze to half way between the min and max lines. She drove the car into the city, the temperature guage is well within the normal area of the guage, however the low coolant light did not go out. When she got back i let the car cool for a few hours and checked the level again and it is right where I filled it to hours earlier. The light is still on today but there has been no loss of coolant at all. Is the level sensor bad or is there another problem going on somewhere.

 

check it inside the radiator too - see if it's low there... sometimes, if there is an air pocket between the levels, it won't draw in anything from the overflow... BTW do this ONLY when engine is cold...

If it's full when you pop the cap, it's most likely a bad sending unit for that sensor, or a shorted wire - but better safe than sorry - don't want to run it low/out of coolant hehe

 

If after checking the radiator and you fine the reason for the light being on, for the coolent leval needs to be at the top of the radiator with only room for the cap to securely and tightly twist onto the radiator. Also check for leaking upper and lower radiator radiator hose's. Check the radiator itself for possible leak's from the core itself. Check the condition of the upper and lower radiator hoses and clamps. Check the condition of the coolent. Coolent should be flushed out and changed at least once every two years.