On the 1992 Cabriolet, the housing on the cylinder head for connecting the radiator hose is made of plastic. I discovered this when the housing split into three pieces while I was stopped and idling. I still had an old engine (or most of it) from my 1982 sitting in the garage, and it's housing was aluminum. The '82 part was heavily corroded and the temp probes are completely different, but it was enough to get the car home without resorting to a tow.
I really don't like the idea of using plastic parts in the cooling system, and I'd rather replace the housing with an aluminum one. Does anybody know of a source for an aluminum housing that will use the temp probes from the 1992 Cabriolet? If not, is there an online dealer that would stock the plastic part (getting parts from the local VW dealer has been a hassle in the past)?