Take a coolant preasure gauge an install it on your radiator, and do not pump it , just crank it, an allow it to run an see if the gauge moves, up, if it runs for more then 15mins, an doesnt move, then rev engine up for a few mins, about 2500-3000 rpms, if it moves anywhere, 5lbs or more, then you got a warped, head or , bad gasket , !