still overheating

i replaced the cam belt and during so i needed to empty out all the water from the engine, since reassembly and refilling cooling system i experiance overheating, heater is cold, seems to have no circulation in the radiator. As suggested by a reader i parked the car on my steep driveway to "burp" the cooling system, i spent 40 mins doing so with little or no noticeable result. Is there something i have done wrong here, the motor is running very well so belt is installed correctly, is there a trick to this problem, 1996 250T 4WD station wagon, can anyone offer help here????, thx andy