Fuel Filler Cap: Description and Operation

Operation
The fuel filler cap is a pressure-vacuum type. A built-in torque-limiting device on the cap prevents overtightening and also eliminates the escape of fuel vapors. To install, turn the cap clockwise until a clicking noise is heard. This indicates that the cap is fully seated.

Vacuum Relief Valve
A vacuum relief valve is incorporated into the fuel filler cap. If the pressure in the fuel tank becomes negative(vacuum), the relief valve opens to release the pressure created within the fuel tank. Only when the vacuum becomes excessive within the tank does this occur.

Pressure Relief Valve
A pressure relief valve is locate in the fuel filler cap. If the pressure of fuel vapor within the tank should exceed that for which the fuel system is designed, the pressure relief valve opens, and excess pressure is vented to the atmosphere.

Notice: If a fuel filler cap is to be replaced, use only a cap with the same features. Failure to use the correct cap can result in incorrect operation of the fuel delivery system.