I have recently had a new head and a heater matrix. the radiator pipe thats conected to the water container thing? (to the right of the engine bay, lol) while the car is running its slightly sqeezable which u would expect, however when i turn the engine off it becomes solid, as if there is a build up of pressure? i know corrados have a high pressure engine and do run hot.... but should the pipe become solid? please help! thanks alot )