An outboard motor includes a water jacket provided in a water-cooled engine, a first channel configured to allow a downstream-side end of a coolant flow of the water jacket to communicate with the external air, a thermo-valve provided between a downstream-side end of the coolant flow of the water jacket and an upstream-side end of the coolant flow of the first channel, a second channel configured to allow an upstream side of the coolant flow of the thermo-valve to communicate with the external air, and a second valve configured to open or close a second channel.

A cap (20) for a header box of a heat exchanger (1), in particular for a motor vehicle, in particular a radiator, is disclosed. This cap includes a head (21), a shank (22) comprising at least one mounting thread (23), this shank being between the head and a free end of the cap, a retaining lug (30), in particular elastically deformable, arranged to retain the cap in an opening (10) of the header box in an intermediate position of the cap, in which position the cap leaves a clear passage while being retained in the opening, this retaining lug being formed on the shank.

A pressure cap for a cooling system of a vehicle may include a reservoir fill port which is mounted at an upper portion of a reservoir in which cooling water is stored in a cooling system of the vehicle; an external cap for closing an upper end portion of the reservoir fill port; a pressure valve disposed in the reservoir fill port to allow the inside and the outside of the reservoir fill portion to fluidically-communicate with each other; a valve seal provided to allow the air to flow from the outside into the internal to the cooling system by being deformed when pressure in the internal to the cooling system is lower than a predetermined pressure; and a positive pressure spring elastically supporting the pressure valve such that the pressure valve closes the internal to the reservoir fill port.

An outboard motor includes a water jacket provided in a water-cooled engine, a first channel configured to allow a downstream-side end of a coolant flow of the water jacket to communicate with the external air, a thermo-valve provided between a downstream-side end of the coolant flow of the water jacket and an upstream-side end of the coolant flow of the first channel, a second channel configured to allow an upstream side of the coolant flow of the thermo-valve to communicate with the external air, and a second valve configured to open or close a second channel.

A radiator cap includes a top cover unit, an intermediate seat unit, an output valve unit, and an input valve unit. The top cover unit includes cover body, a stem, and a plurality of positioning member to be fastened to a radiator opening. A washer surrounds the stem. The intermediate seat unit includes a connecting tube and a connecting seat connected to each other. The output valve unit includes a valve seat connected to the connecting seat. The valve seat has hook portions engaged with guiding recesses of the connecting seat. A valve disc is connected to the valve seat. A first spring is disposed between the valve seat and the connecting seat. The input valve unit includes a pin rod, and a second spring to bias the pin rod to thereby abut against the valve disc so as to close a valve hole.