DETROIT DIESEL 53
Preventive Maintenance 15.1
A method of determining when elements are plugged to
the extent that they should be changed is based on the
Remove the dirty oil and sludge from the oil bath-type
fuel pressure at the cylinder head fuel inlet manifold and
air cleaner cups and center tubes every 8 hours (every
the inlet restriction at the fuel pump. In a clean system,
6,000 miles for highway vehicle engines). or less if
the maximum pump inlet restriction must not exceed 6
operating conditions warrant. Wash the cups and
inches of mercury. At normal operating speeds (1800-
elements in clean fuel oil and refill the cups to the level
2800 rpm), the fuel pressure is 45 to 70 psi. Change the
mark with the same grade of heavy duty oil as used in
fuel filter elements whenever the inlet restriction
the engine. The frequency of servicing may be varied
(suction) at the fuel pump reaches 12 inches of mercury
to suit local dust conditions.
at normal operating speeds and whenever the fuel
pressure at the inlet manifold falls to 45 psi.
It is recommended that the body and fixed element in
the heavy-duty oil bath type air cleaner be serviced
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
inlet housing indicates the maximum allowable air inlet
restriction (Section 13.2).
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
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
1972 General Motors Corp.
SEC. 15.1 Page 5