Recently I encountered my first oveheat problem, so I figured I'd probably let the coolant level in my tank get too low and sucked up some air. Following a procedure discussed here numerous times, I attached a rubber hose to the nipple on the bleeder screw, started the car, let it warm up, then loosened the screw to let air out. To my surprise, nothing came out at all. I loosened the screw to the point of removing it entirely. Nothing. No water, no air. The belt is definitely on and appropriately tight. Is there something else I should be checking, or is my water pump history? -andrew #4115 Houston TX