to the extent that they should be changed is based on
air cleaner cups and center tubes every 8 hours or less
the fuel pressure at the cylinder head fuel inlet manifold
if operating conditions warrant. Wash the cups and
and the inlet restriction at the fuel pump. In a clean
elements in clean fuel oil and refill the cups to the level
system, the maximum pump inlet restriction must not
mark with the same grade of heavy duty oil as used in
exceed 6 inches of mercury. At normal operating
the engine. The frequency of servicing may be varied
speeds (1800-28()0 rpm), the fuel pressure is 45 to 70
to suit local dust conditions.
psi. Change the fuel filter elements whenever the inlet
restriction (suction ) at the fuel pump reaches 12 inches
It is recommended that the body and fixed element in
of mercury at normal operating speeds and whenever
the heavy-duty oil bath type air cleaner be serviced
the fuel pressure at the inlet manifold falls to 45 psi.
every 500 hours, 15,000 miles or as conditions warrant.
Clean or replace the element in the dry-type air cleaner
when the restriction indicator instrument indicates high
restriction or when a water manometer reading at the air
Remove the dirty oil and sludge from the oil bath-type
inlet housing indicates the maximum allowable air inlet
restriction (refer to the Air Inlet Restriction chart in the
Trouble Shooting section). Refer to the instructions in
the Air System section for servicing the dry-type air
With the engine running, check for flow of air from the
air box drain tubes every 1,000 hours or 30,000 miles.
If the tubes are clogged, remove, clean and reinstall the
tubes. The air box drain tubes should be cleaned
periodically even though a clogged condition is not
apparent. If the engine is equipped with an air box drain
tank, drain the sediment periodically. If the engine is
equipped with an air box drain check valve, replace the
valve every 500 hours or 15,000 miles.
Clean the externally mounted crankcase breather
assemblies every 1,000 hours or 30,000 miles. This
cleaning period may be reduced or lengthened
according to severity of service. Clean the internally
mounted breather pads at time of engine overhaul, or
sooner if excessive crankcase pressure is observed.