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Flushing and Filling Your Car’s Radiator

Inspect your radiator and radiator hoses for rust or weak spots. If there is no rust or damage and the hoses are not cracked or collapsed, proceed. If damage is detected, take to your local, trusted car care professional.

Make sure that the vehicle has not been driven for at least 2 hours to prevent injury.
Jack up the front end of your vehicle with the parking brake set. Locate the radiator petcock and place a large drainage pan underneath of it.

Remove petcock and allow fluid to drain. Remove drain pan and replace petcock.

Fill radiator with water and radiator cleaner. Run vehicle for 10 minutes. Shut off vehicle.

Allow to cool for 30 minutes. Using another large catch pan, place it under the petcock, then remove the petcock, allowing the fluid to drain.

Repeat the process at least once more, depending on how dirty the fluid is that is draining out.

Replace petcock for the final time. Inspect thermostat, if there are any cracks in the seal,replace thermostat with a new one. Following your cars manufacturers repair manual, fill radiator with a 50/50 mixture of water to antifreeze. Remove radiator cap and inspect. If seal is cracked, replace with a new one. Leaving the radiator cap off, run engine for approximately 10 minutes to remove air bubbles. Refill with antifreeze and water as necessary. Replace radiator cap. Take used fluids to your local car care professional for safe disposal.