im still not entirely sure whether the engine in my car is an s4 or an s5 engine, but it does have the S4 water pump, and im not sure if there would be any reason why an s5 engine would have an s4 water pump on it.

 

It could be because the s5 uses a plastic thermostat housing... super gayyyy

 

Water pump series goes with the right water pump housing. Maybe the previous person didn't want the plastic goose neck.



Is kind of hard to put a S4 water pump housing on an S5 because the lower intake tube will hit the OMP unless it was removed before.