This condition just started to really get worse in the past few weeks and i am afraid trhis summer i will not be able to drive the car. Well this is the problem, it is a 89 mustang gt with a 302 HO EFI, underdrive pullies, 180 degree thermostate, K&N, and an H-Pipe otherwise a stock motor. Well when the car sets and idles it slowly climbs on up to 250 degrees and then overheats. It is also using water, not alot but it is using water. I left it in the garage for 2 days and no water on floor and no visible leaks so it has to be using it. Could is be a possible head gasket or do you think the heads are gone for good? Or does anyone else know of a condition to cause this problem. Going down the road at 60 it runs a cool 170* But in heavy traffic and stop lights it rises to about 200* to 220* Also one more thing, when i cut the car off the temp guage goes on past 270* Thanks for any and all the help!!!!