Ok maybe I didn't explain it properly but the thermostat housing itself is not the problem, that isn't leaking. Basically the plastic pipe that come off it and sits inside the rubber hose has completly snapped clean off. I noticed that's where it was leaking water and unclipped the rubber hose off it and the plastic part came clean off and stayed inside the pipe, it just looked like it had become brittle over time and the hot water had just eaten it away? So I really need to get a new one or do you think that I might be able to glue it back on if I use some strong glue? I'm at college at the mo so don't know what the part number is but just zoomed in the pic iv got and this what I think it says, vw then the 4 Audi rings, made in west Germany, 535 121 647.