Let the engine cool completely
Park on a level surface and set the parking brake
Place a drain pan under the radiator drain plug or lower hose
Open the radiator cap only when the engine is cool
Open the drain plug or remove the lower radiator hose to drain the coolant
Drain the coolant from the engine block if equipped with a block drain plug
Close the drain plug or reconnect the lower hose
Fill the system with distilled water or a radiator flush solution
Start the engine and run it with the heater on until it reaches operating temperature
Turn off the engine and let it cool completely
Drain the flush mixture again
Repeat with distilled water until the drained liquid runs clear
Close all drains and reconnect all hoses
Refill with the correct coolant mix specified by the vehicle manufacturer
Bleed air from the cooling system
Check the coolant level after the engine cools and top off if needed
Inspect for leaks around hoses, clamps, drain plugs, and the radiator cap
Dispose of old coolant properly