i just got my motor completely rebuilt including a 2.0mm metal hg and ARP studs. the head and block both were resurfaced and the head got a 3angle valve job and so on. well ever since first start up the car leaks antifreeze out of the overflow tank, and it gets worse as the car gets hotter. the car does not overheat just throws the coolant out of the overflow. is this a problem with the hg leaking or could it possibly be something else?