On the side of the radiator, down by the bottom, there should be a drain screw (pit cock). Unscrew this and it will allow the coolant to drain. You will also want to loosen the radiator cap to release the vaccume. Make sure that you drain it into a container and dispose of it properly. Cat and dogs love the antifreeze, but it will kill them. Once the radiator has drained, tighten the pit cock and refill with antifreeze. If you don't want to mess with it, most quick oil change places will flush it out for you pretty cheap. I think the one by my house charges $15.00 or so? Not too bad considering a gallon of antifreeze costs about $12.00. Also, follow the directions on the antifreeze for dilution. You don't want to put straight antifreeze in your car. It needs to be mixed w/ water. Any problems, just let me know. I'll be happy to help. Good Luck.