Overheating engine while car is idle?

A lot of vehicles require the cooling system to be bled of air, especially if you've had a leak or have done any cooling system repairs. You may have air trapped that is not letting the coolant circulate properly. Look at the thermostat housing for a bolt that is in the crown. With the engine cool and off, remove the bolt and top off the radiator until the air bubbles stop coming out and a steady stream of coolant is flowing out. Then reinstall the bolt and top off the radiator.