You will first need to drain the old coolant from your cars radiator. If you have an owner’s manual it will tell you where the drain plug is located. If not look underneath the radiator for a petcock, screw, plug or bolt. Make sure when you are draining the coolant that it goes into a container and not the ground. With the container in place unscrew the drain plug and let the coolant empty out completely. If your radiator is set up with a petcock, make sure and open it all the way. If you have a drain plug that is a screw or bolt remove it completely from the radiator. After the coolant has drained from the radiator, put the drain plug back in and take off the radiator cap. Put the radiator flush solution into the radiator, then add water to the top of the filler neck on the radiator.
Put the radiator cap back on and make sure it is tight. Next start your car and let it run until it gets to operating temperature. You will also want to turn your car heater on to the highest temperature setting so the cleaning solution will circulate through it. Let the car run for an additional 12 minutes. Next turn the car off and let the engine cool down. Do not take off the radiator cap until you can touch the cap safely. If the cap is to hot to touch, the engine has not cooled down enough. After the engine has cooled down remove the drain plug and drain the radiator empty into a container. Do not let the cleaner get on the ground. Make sure and have a second container available if the first one fills up. Your radiator flush is complete. Replace the correct coolant back into your radiator and tighten the cap. Run the engine one more time, let cool and recheck your coolant level.