2003 Cavalier Air in Coolant System

Is the heater core plugged ?

With the engine cold, remove the coolant recovery tank cap. Remove the upper radiator hose at the engine, thermostat housing, and thermostat. Pour the coolant into the engine through the hole where the thermostat goes. Continue pouring until the engine is full. Now, put the thermostat, thermostat housing, and upper radiator hose back on the engine. Now, fill the plastic coolant recovery tank with coolant up to the full cold line. Start the engine. Top off the recovery tank as needed. Let the engine run until it's up to normal operating temperature. As the engine warms up, keep an eye on the recovery tank. If the coolant level begins to rise, the system is full and you can put the cap on the recovery tank. Once the thermostat opens the coolant level may drop. If that happens, simply top off the recovery tank once more after the engine has cooled off. Hope that helps! Jim