Rollover Valve (Fuel Check Valve)

Fuel Check Valve:

The fuel check valve, is used to prevent fuel leaks should the car suddenly roll over. This valve is connected in the fuel vapor line (between the canister and overfill limiter) and is mounted on the firewall. Under normal conditions, the gasoline vapor passage in the valve is opened, but if roll over occurs at least one of the two balls closes the fuel passage preventing fuel leaks.