TM 5-3810-300-24 & P2
down the wall of the body and is ejected into a dust cap. The dust cap is baffled to prevent re-entry of dust. The pre-
cleaned air passes through the paper filter and enters the engine.
Air Box Drains.
During normal engine operation water vapor from the air charge, as well as a slight amount of fuel and lubricating oil
fumes, condenses and settles on the bottom of the air box. This condensation is removed by the air box drain tubes
mounted on the side of the cylinder block.
The air box drains must be open at all times. With the engine running, a periodic check is recommended for air flow from
the air box drain tubes. Liquid accumulation on the bottom of the air box indicates a drain tube may be plugged. Such
accumulations can be seen by removing the cylinder block air box cover(s) and should be wiped out with rags or blown
out with compressed air. Then remove the drain tubes and connectors from the cylinder block and clean them
thoroughly.
Crankcase.
Harmful vapors which may form within the engine are removed from the crankcase, gear train, and injector compartment
by a continuous, pressurized ventilation system.
A slight pressure is maintained within the engine crankcase and injector compartment by the seepage of a small amount
of air past the piston rings.
Crankcase ventilation is accomplished by the air seepage past the piston rings sweeping up through the flywheel housing
and balance weight cover into the valve and injector rocker arm compartment where it is expelled through a vent pipe
attached to the rocker cover or the governor. Certain engines use a breather attached to the side of the cylinder block.
Manual Air Shut-Off Valve.
In an emergency, a emergency stop knob located in the cab may be pulled to stop the engine. The emergency stop knob,
when pulled, will trip the air shut-off valve located between the air inlet housing and the blower and shut off the air supply
to the engine. Lack of air will prevent further combustion of the fuel and stop the engine.
The emergency stop knob must be pushed back in after the engine stops so the air shut-off valve can be opened for
restarting after the malfunction has been corrected.
Lubricating System Components.(Illus. 4-6).
This lubricating system consists of an oil pump, oil cooler, a full-flow oil filter, by-pass valves at the oil cooler and filter
and pressure regulator valves at the pump and in the cylinder block main oil gallery. Positive lubrication is ensured at all
times by this section. A by-pass oil filter may also be incorporated into the lubricating system.
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