Are you resurrecting this engine from an non operational status or have you just re built it? Are you talking about the pulley on the water pump or the balancer? Had to ask, don't know the history of this thread.
If the leak is at the water pump pulley, you may need a water pump. A quick way to check is to grab the fan blade and check for movement from front to rear at the water pump shaft. If you can get the tester that puts pressure on the radiator that will allow you to check for leaks at the shaft and anywhere else.
If you have water at the balancer, it probably coming from somewhere else and collecting there somehow.
Attempted to resurrecting. It's coming from the pulley at a pretty good clip. When we bought the truck that radiator had been pulled so I'm sure that was the reason that was one of the causes for it being parked. At least I have learned to just fill with hose water rather than loosing distilled water/coolant.
