I just want to hear a few opinions. This week the LOW COOLANT light on my Grand Prix came on Monday morning. The overflow container was at about the rubber line. I went ahead and put some more fluid in anyway, and the light eventually went out. Now, after the car has been cool for several hours, particularly in the morning the light is on. I don't see any obvious leaks underneath, and the level hasn't changed since i filled it. In April i replaced the UIM. Also, I didn't see any coolant in the oil when I looked at the dipstick. I'll know for sure in a few days when I change the oil.
Anyway, is it likely I have a bad coolant sensor? It's approximately $40 piece, so I won't sweat it if has to be replaced. But if I don't replace it, what kind of danger am I doing by not yet replacing it.