I would check first to make sure you have bled all the air out of the cooling system. With the engine completely cool, remove the radiator cap, fill the with coolant if needed. Leave the cap off, start the car and turn on the heat, and let it run till it reaches normal operating temperature and the thermostat has opened. You may need to raise the rpm a couple times to help push the air out. Also check the heater hoses at the firewall on both sides to be sure that both hoses are hot. If only one hose is hot (supply) and the other hose cold then I would say the heater core is clogged (if there was a lot rust in the coolant). If only the supply hose is hot then you can remove both the heater hoses, Take a garden hose and force water into the heater core to unclog it. If you have exhausted all these options then I would move on to be sure your blend door is moving to actually let the hot air in.
Nov 11, 2014 at 11:54 PM
