The water pump on a 2001 Pontiac Grand Prix is located at the
front of the engine, typically driven by the serpentine belt. It's usually near the timing belt or timing chain (depending on the engine type - 3.1L V6 or 3.8L V6). You'll have to get under the hood to see it, and it will be on the engine block itself, generally near the bottom of the engine, but fairly centrally located in the front.
Because of the location and the need to access it for maintenance or replacement, it is often considered a somewhat difficult part to replace, usually requiring the removal of other components.
