K 3500 Truck 4WD V8-393 6.5L DSL Turbo (1993)
Fuel/Water Separator: Description and Operation
Fuel Manager/Filter Assembly
PURPOSE
The diesel engine fuel filter is an inline type filter which combines several different functions. It acts as a filter, water separator, water detector,
water drain, and fuel heater.
OPERATION
The first stage of the filter element is a water coalescor. The coalescor element combines small droplets of water into large drops. The water
collects in the bottom of the filter element for draining.
The fuel then passes through the second stage of the filter element which is a paper filter. The filter acts as a water detector by turning on the
"WATER IN FUEL" light on the instrument panel. When 65 ml (2.2 fl oz) of water has collected in the filter, the probe of the water detector will
contact water. This completes a circuit through the water to the cover assembly which turns on the "WATER IN FUEL" light.
A water drain is located in the bottom of the fuel filter assembly. By opening the water drain valve, water that has collected in the bottom of the
filter element can be drained.
A fuel heater is located in the fuel filter assembly to help prevent fuel waxing. The heater thermostat turns the heater on at about 8°C (46°F) and
off at about 25°C (77°F). The heater uses 7 to 13 amps depending on fuel temperature.
LOCATION
The fuel filter is mounted on rear top of intake manifold.
