to Red, with cold engine? This car has a small coolant leak at the overflow tank. But not all the time, only if i overfill it. But the temp guage has never been reliable either. Today suddenly the car overheated, the computer THOUGHT it did. It was only running 10 minutes. and i shut it off and the temp went down to half within 5 minutes. Start it up, it shot up to the red again within 20 seconds? Ever happen like this for anyone else?