Thermostat

Where is the thermostat located in a 1997 buick century? We replaced the water pump because there was a leak and we also replaced the hose going to the pump. There still seems to be a very small leak. Car is really overheating in traffic could changing the thermostat fix this problem?
how can you tell if there is air trapped in the rad or hoses? read on one of these posts about that?

Usually where the top radiator hose connects to the engine. And yes changing a thermostat would be in order for this problem.