Let the engine cool completely
Park on a level surface and set the parking brake
Open the hood and locate the radiator cap and drain plug
Place a drain pan under the radiator
Remove the radiator cap
Open the drain plug or petcock and drain the coolant
Close the drain plug once drained
Fill the radiator with distilled water or a radiator flush solution
Start the engine and run it with the heater on for the recommended time
Turn off the engine and let it cool completely
Drain the radiator again
Repeat with distilled water until the drained water runs clear
Close the drain plug securely
Refill with the correct coolant mix
Bleed air from the cooling system if required
Reinstall the radiator cap
Check for leaks
Dispose of old coolant properly