water leak

my friend has a 1993 sentra 4cyl we changed the water pump but it is leaking at or around the top of the pump somewhere.
after we changed the pump i went home he said he filled it with water and noticed a water leak around the top of the pump somewhere.
should we use stop leak or what

no, take it back off and see why it is leaking. re-seal with new gasket and use gasket sealer. make sure all surfaces are clean and dry before putting sealer on. denatured alcohol does a good job for this. make sure you have all the bolts in the right spots. some may be longer than others.