Thema water pumps are very similar. The difference is effectively to do with the 16V cylinder head having the rearmost camshaft further back when compared to an 8V head. The result of that is that the timing belt runs closer to the water pump, in fact too close! The 16V pump has less metal around the body of the pump so as to provide more space for the belt. When running the timing belt has a bit of whiplash that causes it to move close to the pump body.

The 8V specification pump can be modified to fit a 16V engine by removing metal to ensure that it has the same shape and profile.