97 intrepid over heating problem

i just got a 97 intrepid with 3.5 in a package deal. the engine seems to run fine but is over heating. i noticed the coolant tank leaking under the cap so i replaced that. was gona replace the thermostat but it was missing:runaround:. i found a few vacuum leaks and fixed them. when refilling the radiator i was bleeding off the air from the thermostat housing and desided to give it some throtal to see how much pressure the water pump was putting out. it didnt seem like a lot but it would put out a little more water. could it be a bad water pump ? and how could i know for sure ? im used to the old style that would leak water when they went out but ya cant even see this one