I just changed my head gaskets and the motor has about 30 miles on it. Every time i open the radiator after it cools down the water is about 2 inches below the cap. I fill it back up no matter how far or long i run the car it does the same thing. I bought a new radiator cap and it is still not pulling the water from the overlow back in the tank when it cools down. the overflow tank is full all the time. i just had it pressure checked for leaks and none were found. how long does it take to work all of the air pockets out of the motor? Any suggestions?