D 250 Pickup L6-359 5.9L DSL (1992)
Evaporative Check Valve: Description and Operation
Pressure Relief/Rollover Valve
OPERATION
All vehicles have a combination pressure relief and rollover valve. The rollover valves relieve fuel tank pressure. They also prevent fuel flow
through the fuel tank vent hoses if a vehicle rollover occurs.
The valve incorporates a pressure relief mechanism that releases fuel tank pressure to atmosphere when fuel tank pressure increases above
calibrated sealing value.
