Permanently and reliably seals hairline cracks and leaks in the radiator, water pump, cylinder head and engine block. Eliminates the need for expensive repairs. Protects the entire cooling system from rust and corrosion. Lubricates the water pump. Acid-free and non-toxic. Does not damage rubber hoses, metal parts and gaskets. Suitable for all aluminum, plastic and steel cooling systems in gasoline, diesel and LPG engines. Compatible with water, coolant and conventional antifreeze. Not suitable for cooling circuits with internal filter unit. How to use: Shake well before use. Add the contents of the can to a slightly hot (not boiling) cooling system with the engine off. It is recommended to pour the contents directly into the radiator. Alternatively, if the radiator is a closed system, the contents can be added to the coolant reservoir. After adding, turn off the cooling system, start the engine and let it run for 10 minutes or drive a short distance with the heater on. Important: Caution when opening the coolant / cooling system: Hot coolant or vapor can escape from the system! Dirty cooling systems must first be cleaned with WINKEL Radiator Cleaner. Dosage: One bottle is sufficient for cooling systems with a volume of up to 12 liters.