1984 Buick Skylark overheating

If you have no leaks and it overheats, then fill it up with coolant, making sure it's cool when you do this. Drive it until it overheats then shut the car off. then open the hood and with the car off place your hand on several spots on the radiator backside. If you feel any spots that it is cold or not the same temp as the rest of the radiator then you need another one. If there are any loose rows of fins or greenish looking ones you also need another one.