My water pump was leaking so I decided to swap it out with a new water pump and thermostat. Well I just got back from my test run and the car nearly over heated! Do I need to bleed anything out? Someone stopped who saw my hood up and said that I may have gotten some air into the system? Will that make a difference or could this be a bad pump or the thermostat stuck? Thanks for your help!

My water pump was leaking so I decided to swap it out with a new water pump and thermostat. Well I just got back from my test run and the car nearly over heated! Do I need to bleed anything out? Someone stopped who saw my hood up and said that I may have gotten some air into the system? Will that make a difference or could this be a bad pump or the thermostat stuck? Thanks for your help!

Sounds like you most likely got some air in the system... check your water levels, I have personally never had a bad thermostat out of the box.