Does not harm your vehicles engine. Safe and easy to use. Permanent repair. Directions: Cooling system must be clean and free flowing before applying the sealer. Remove thermostat and flush cooling system using a radiator flush and then flush with water. Fill cooling system with water. Leave enough room for the recommended amount of BlueDevil that shows applications on the bottle. Engine must be cold before you begin. Remove the radiator cap and start the engine while cold then turn heater to Max. While the engine idling pour BlueDevil into the radiator slowly (take 1 minute pour time for entire bottle 30 seconds for 1/2 bottle). After pouring BlueDevil slowly let vehicle idle with cap ON for 50 minutes. You do not need to flush the system a second time after process is complete. Let engine cool before installing new thermostat. Drain enough fluid to refill with compatible antifreeze.
