Feels (Honda Twincam) 1.35 Bar Radiator Cap For Honda Civic Type R - FD2RRaise the boiling point of your coolant for increased cooling efficiency and prevention of over heating with a high pressure radiator cap. By changing the stock radiator cap with a higher pressure one, the internal pressure of the radiator is increased resulting in a higher boiling point. When coolant boils, small air pockets are created. As the coolant passes through the block and radiator core, the air pockets reduce the cooling efficiency and will