Cooling system expansion tank

摘要

An expansion tank 21 for a cooling system of a liquid-cooled internal combustion engine is disclosed. The tank comprises a plastic housing having an inlet port for connection to a supply of coolant discharged from the engine and an outlet port 27 located at the bottom of the tank for the return of coolant to the engine via a return conduit 23. A non-return valve 30 is located in the outlet port to limit coolant backflow into the tank through the outlet port. Preferably, the outlet port of the expansion tank has a surface forming a valve seat (28, fig.4), and the non-return valve has a valve head (33, fig.4) shaped for cooperation with the valve seat. In use, in the event that the pressure in the expansion tank falls below the pressure in the return conduit, the non-return valve prevents the expansion tank from filling with coolant. In further embodiments, degas circuits comprising the expansion tank are also disclosed.