D 350 Pickup L6-359 5.9L DSL (1989)
Fuel Drain Manifold: Description and Operation
FUEL DRAIN MANIFOLD
The fuel system is designed to use fuel to cool and lubricate the injection pump and injectors Fuel is continually vented from the injection pump
and a small amount of fuel leaks by the injector needle valve during injection. This fuel is returned to the supply tank by the fuel drain manifold.