Fuel Filler Cap: Description and Operation
PRESSURE-VACUUM FILLER CAPThe loss of any fuel or vapor out of the filler neck is prevented by the use of a safety filler cap. The cap will release pressure only under significant pressure of 10.9 - 13.45 kPa (1.58 - 1.95 psi). The vacuum release for all gas caps is between 1.94 - 2.94 kPa (0.28 - 0.43 psi). The cap must be replaced by a similar unit if replacement is necessary.
WARNING: REMOVE FILLER CAP TO RELIEVE TANK PRESSURE BEFORE REMOVING OR REPAIRING FUEL SYSTEM COMPONENTS.