Q: Car running hot

If the vehicle was not overheating prior to the replacement of the water pump, there are two obvious possibilities: when adding coolant back to the system, all air was not purged from the cooling system; and/or, the water pump doesn’t work. Trapped air is a cause of overheating and if the pump drive belt is not properly tensioned, the pump runs at inadequate speed. Apart from those two possibilities, this failure (that is, the present overheating that perhaps did not exist prior to the repair) could be due to a faulty thermostat, a plugged radiator, a collapsed hose, inadequate coolant level, and so forth. If you desire that this problem be diagnosed by a certified Mechanic, dispatched by YourMechanic right to your location, please request an engine overheating diagnostic and the responding mechanic will get this resolved for you. If you have further questions or concerns, do not hesitate to re-contact YourMechanic.