PRINCIPLES GASOLINE/DIESEL FUEL SYSTEMS - OD1620 - LESSON 2/TASK 2
Diesel fuel oil filters are referred to as full-flow
filters, because all the fuel must pass through them before reaching the
injection pumps. A diesel fuel filter usually incorporates an air valve to
release any air that might accumulate in the filter during operation.
(1) Primary Filters (figure 64). Metal filters are used as primary
filters because the fine particles that will pass through them are not
injurious to the supply pump.
Solids larger than 0.005 in. remain outside the metal disks,
while larger foreign matter and the majority of the water settles to the
bottom of the bowl. From here, the foreign matter can be removed through a
PRIMARY FUEL FILTER.
(2) Secondary Filters (figure 65 on the following page).
filters, because of their greater filtering qualities, are most commonly