I need to replace my thermostat housing on my c5 A6 2.7t. Mine is a 2002 but I notice on earlier models, they used a metal housing and mine uses plastic. Anyone know if they are exchangeable? I do notice it is missing a lower bolt hole but not sure if that actually matters. It's more expensive but I'd love the piece of mind knowing it won't crack. Anyone try it? Search yielded nothing.

 

It hasn't been discussed in a long long time. From what I remember, they are interchangeable (but verify before ordering). As you know the plastic ones will crack when over tightened. I would just keep the plastic one and when you do the thermostat make sure you don't over tighten it.