B250 3/4 Ton Van V8-318 5.2L VIN T FI (1992)
Fuel Filler Cap: Description and Operation
Pressure-Vacuum Filler Cap
OPERATION
The fuel tank is sealed with a pressure-vacuum relief filler cap. The relief valves in the cap are a safety feature. They prevent excessive pressure or
vacuum in the fuel tank. Excessive pressure or vacuum could be caused by a malfunction in the system or damage to the vent lines.
The cap has a threaded configuration which allows the seal to be broken. It also allows pressure to be relieved without separation of the cap from
the filler tube. Approximately two and one half turns are required to remove the cap.
To be sure of correct fuel system operation, only use an identical cap if replacement of the filler cap is necessary.
