[pcv]

Check the coolant when the car is cold. You either have a leak or your are burning coolant. More than likely it is a leak. Pressure test the cooling system and correct the leak. A thermostat and gasket would be a bonus.
The special procedure is to make sure there are no air pockets in the cooling system. On top of the thermostat housing is a little bleeder screw. Open it and with the car running, let all the air out. Once coolant comes out of it, close it tight. Run the car and make sure the radiator fan comes on.