ok, My 84 vanagon waterboxer 1.9  is over heating when I take it up through the gears... It boils!! I have checked the thermostat .. flushed the system ( cold, hehe) added a new waterpump, blead it many times but it still finds a way to overheat and boil. It is not leaking any coolant on the ground but I have heard that another form of head gasket leak is internal, though rare... Anyone have this experience and what did you do with it?? I need help!!!