there are 2 belts, one for the water pump, which is quite small, and the serpentine belt on the other side of the engine. I would definitely replace the wp belt, since you have to take it off to change the pump. Examine the serp belt, and if it looks dry with lots of cracks or sections of rubber missing, change it also. This one can always be done independently since it has nothing to do with the waterpump at all. I would change the thermostat & o-ring when doing the pump, since you have that area accessible. When you have the wp impeller section removed, check the metal plate (cone) that's in the housing that remains on the engine for signs of looseness. If it's loose in any way, go back to the parts store and buy the complete water pump assembly. Then you'll really be good to go!
