First clean the cooling system with TecLub Radiator Cleaner. Let the engine run for 15 min. Drain this mixture and flush the system with water. Refill system with water. Remove the thermostat and upper radiator hose. Shake the bottle of Cylinder Block Seal well before use. Pour Cylinder Block Seal into the opening of the removed thermostat. Reconnect the radiator hose to close cooling system again (thermostat is NOT mounted). Let the engine run for 15 to 20 minutes. Check water temperature during treatment. Stop the engine. Drain when engine is cold (!) and flush with water. Fill with recommended coolant. Remount the thermostat again.
Follow normal procedure, but leave Cylinder Block Seal in the cooling system for 4-5 days before flushing with water and refilling with recommended cooling liquid. Make sure cooling system and engine do not get overheated.
One 250 ml bottle is sufficient for cooling systems with a volume of up to 8 litres.