Abstract: A radiator cap sets on a filler neck of an automotive radiator tank. The radiator cap has an inner cap rotatably connected with an outer cap, a pressure valve operatively connected with the inner cap in such a manner that the pressure valve can move vertically so that the pressure valve opens the filler neck when the pressure within the radiator tank increases up to a predetermined pressure. The radiator cap further includes a coil spring provided between the inner cap and the pressure valve for biasing the pressure valve toward the filler neck. Since the connecting point between the coil spring and the pressure valve is lower than the connecting point between a sealing portion of the pressure valve and the filler neck, a rotating moment which returns the pressure valve horizontally is generated when the pressure valve is inclined, preventing the pressure valve from inclining.

Abstract: A radiator for an automotive engine has a filler neck having a coolant pass therein. The filler neck has both an inner tubular member and an outer tubular member so that the coolant pass is formed between the inner surface of the outer tubular member and the outer surface of the inner tubular member. The coolant pass is connected with a connecting pipe in order to introduce the coolant within the coolant pass toward the connecting pipe. The coolant introduced into the connecting pipe is, then, flows toward a reserve tank.Since all coolant flowing toward the connecting pipe is orientated its vector while passing through the coolant pass, the coolant can be introduced into the connecting pipe smoothly.

Abstract: A radiator cap composed of a cap body, a compression gasket assembly connected to the cap body and adapted to open and close in accordance with the pressure of the coolant in the radiator, a float engaged with the cap body so as to move up and down in accordance with the level of the coolant. The upper edge of the float is formed so that upon contact with a gasket assembly, a valve is formed with said gasket assembly. A reed switch secured to the cap body is opened or closed in response to movement of the float so that the reed switch actuates suitable warning means when the level of coolant falls over a predetermined line.