[Sean Marconette]

Rory,

Take your housing that has the grove in it, you should be able to match up the diameter and O-ring size at a hardware store. You will probably have to glue the O-ring in the groove to keep from cutting it, when you install it. The original water pump was a reverse rotation due to the serpentine belt rotating the pump backwards, compared to a conventional V-belt drive system.

Sean