I have a 97 Taurus that is losing coolant water out of the radiator cap. It happens whenever I turn A/C on or in hot weather. I have a new cap from Ford a week ago but not help. It is not overheating with normal temp gauge and is not overfilled (it is at bottom line). There is no leak of coolant anywhere else. I had a flusing a month ago. The car runs great and smooth, no strange noise even with 90K miles. I replaced the tank (crack in the bottom) 4 years ago. Anyone know what's wrong with it? Thanks.