Ford Vans 1961-1988 Repair Guides

Fuel/Water Separator



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Fig. Fig. 1 View of the fuel/water separator with drain petcock on the bottom

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Fig. Fig. 2 Exploded view of the fuel/water separator-diesel engines

The 6.9L and 7.3L diesel engines are equipped with a fuel/water separator in the fuel supply line. A Water in Fuel indicator light is provided on the instrument panel to alert the driver. The light should glow when the ignition switch is in the Start position to indicate proper light and water sensor function. If the light glows continuously while the engine is running, the water must be drained from the separator as soon as possible to prevent damage to the fuel injection system.

  1. Shut off the engine. Failure to shut the engine off before draining the separator will cause air to enter the system.
  3. Unscrew the vent on the top center of the separator unit 2 1 / 2 to 3 turns.
  5. Unscrew the drain screw on the bottom of the separator 1 1 / 2 to 2 turns and drain the water into an appropriate container.
  7. After the water is completely drained, close the water drain finger-tight.
  9. Tighten the vent until snug, then turn it an additional 1 / 4 turn.
  11. Start the engine and check the Water in Fuel indicator light; it should not be lit. If it is lit and continues to stay so, there is a problem somewhere else in the fuel system.

All but very early production models have a drain hose connected to separator which allows water to drain directly into a container placed underneath the vehicle.