Rear gear train engines use a dual fuel filter system.
• The pressure side fuel filter is used for filtration only and is pressurized by the gear pump mounted on the
engine’s fuel pump.
NOTE: Some applications utilize a chassis-mounted pressure side filter.
• The suction side fuel filter is a fuel/water separator and is located between the gear pump, mounted on the engine’s fuel pump, and the original equipment manufacturer (OEM) fuel supply tank. This filter is
not pressurized, but operates under a vacuum for maximum inlet restriction allowed at the filter. Refer to
Procedure 006-020 in Section 6.
NOTE: Some applications utilize an engine-mounted suction side filter.
Fuel System Priming
A certain amount of air becomes trapped in the fuel system when fuel system components on the supply and/
or high-pressure side are serviced or replaced. Fuel system priming is accomplished using the electric fuel
transfer (lift) pump or manual priming pump. For priming procedures, see the Prime step of this procedure.
NOTE: It is not necessary to vent air from the high pressure fuel system before starting the engine. Cranking
the engine will help prime the fuel system.
