my 03 a4 1.8t heater hose is leaking. its coming from behind the plastic lock fitting where it connects to the metal pipe from the engine. not sure if its the fitting or if the metal pipe from the engine is cracked and leaking. i will be taking it out tomorrow but with one simple question......do i REALLY need this plastic lock fitting or can i just run a straight coolant hose from the metal pipe off the engine to the dash entry? any help would be greatly appreciated!