If the outside housing on the water pump is visibly leaking, you need a new water pump. There are bearings and seals that go around the shaft, and with mileage and/or poor cooling system maintenance, they will fail and leak. There is a 'weep hole' somewhere on the stub that sticks out and it will let coolant out of it when the seal fails.
Other possibilities include a bad water pump gasket, or timing cover gasket. Be aware that when the bolts are removed, some of them need to have a sealant applied to the threads before you reinstall them because they protrude into the coolant passage for the engine. For the timing cover on a 3.0, there are two on the left side, and one on the right. For the water pump, I think there is just one that is that long.
Other possibilities include a bad water pump gasket, or timing cover gasket. Be aware that when the bolts are removed, some of them need to have a sealant applied to the threads before you reinstall them because they protrude into the coolant passage for the engine. For the timing cover on a 3.0, there are two on the left side, and one on the right. For the water pump, I think there is just one that is that long.
