I just bought a 2001 LS from a woman who claimed it had a blown headgasket. When I first looked at the car I topped off the coolant and test drove it. I bought it and drove it for three weeks before the temp came up on me in the Krystal's drive-thru. I pulled over, ate my food, drove home and topped it off again. Haven't had it happen again yet.

Every time I open the radiator cap it releases some wicked pressure. The lady replaced the radiator, cap, hoses and thermostat before selling it.

Dosen't smoke and no coolant in the oil, but there is some coolant loss.
Do you think I have an extremely slow leak in the headgasket?