i am having an overheating problem which has caused my car to sit in my driveway......... mods are listed in sig, car normally runs very cool, by the "a" or "l" on the temp gauge. recently it has decided to overheat on me! it happened one time about 1 1/2 months ago, the temp went all the way up to about 240-250*. i looked for leaks in the cooling system ( hoses radiator etc.) and found none. the antifreeze level was fine. the same thing happened twice this week, and the antifreeze was really low. the car is parked in a garage, and there has been no sign of coolant on the floor. i am wondering if my coolant is evaporating on me for some reason? or maybe the water pump is fainling to turn and the coolant is boiling off? any help would be appreciated!