How to Flush With Stop Leak
- 1). Park the vehicle on a flat surface and turn the engine off, engage the parking brake. Pull the hood latch and open the hood.
- 2). Allow the engine to cool down completely for a couple of hours. Check the radiator cap to see if it is still hot. When cool, unscrew and remove the radiator cap from the radiator.
- 3). Shake the bottle of Stop Leak vigorously. Begin the flushing process by emptying the entire contents of Stop Leak into the radiator.
- 4). Add antifreeze and water to the radiator until it is completely full. Screw the radiator cap back onto the radiator until it is tight.
- 5). Crank the engine and let it idle for at least fifteen minutes at regular operating temperature. Check the radiator and the water pump for leaks. Check for leaks while the engine is running. Turn the engine off and check for leaks again. Allow the engine to completely cool off for a couple of hours before draining the radiator.
- 6). Place a drip pan underneath the drain plug on the bottom of the radiator. Turn the drain plug counter-clockwise with the pliers until the coolant begins flowing out of the radiator and into the drip pan. Wait for all of the coolant and the excess Stop Leak to drain out of the radiator and then retighten the drain plug.
- 7). Fill the radiator back up with antifreeze and water until the coolant level stabilizes at the top of the fill neck. Screw the radiator cap back onto the radiator until it is tight. Crank the engine and allow it to run for about five minutes at operating temperature. After the thermostat opens and allows coolant into the engine, refill the radiator as needed.
- 8). Inspect the radiator and the water pump for any leaks while the engine is running. If the leak continues, turn the engine off and add another bottle of Stop Leak to the system.