Show pix of water pump on2004 Monte Carlo

If it's from the thermostat housing, you can reinstall the housing with a new gasket or use a gasket sealer on it. If it's from the water pump cover same thing, new gasket. If it's leaking from the shaft, you'll need a new water pump. If it leaks from the hose or where hose attaches, replace the hoses or tighten the hose clamp. Since it is leaking, be sure to keep an eye on the coolant level in the overflow bottle, don't let coolant get too low or engine can overheat. Be sure to use the same type of coolant you have now, don't mix colors.