3500 4x4 Pickup L6-359 5.9L DSL Turbo (1996)
Fuel Filler Cap: Description and Operation
DESCRIPTION
The loss of any fuel or vapor out of filler neck is prevented by the use of a pressure-vacuum fuel tank filler tube cap.
OPERATION
Relief valves inside cap will release only under significant pressure of 6.58 to 8.44 kPa (1.95 to 2.5 psi). The vacuum release for all gas caps is
between .97 and 2.0 kPa (.14 and .29 psi). This cap must be replaced by a similar unit if replacement is necessary This is in order for the system
to remain effective.
CAUTION: Remove fuel tank filler tube cap before servicing any fuel system component. This is done to help relieve tank pressure.