Rollover Valve: Description and Operation

Rollover Valve:

PURPOSE AND LOCATION
The two-way valve is located in the fuel vapor line and functions to control pressure in the fuel tank.

OPERATION
When fuel tank pressure is above a certain point, the valve opens to permit fuel vapor flow to the canister. When tank pressure is below a certain point, the valve opens allowing fresh air to enter the fuel tank. A check ball system incorporated in this valve also permits simultaneous function as a rollover valve, preventing fuel leakage in the event of vehicle rollover.