TM 5-3810-300-24&P-3
4.8
VENTILATING SYSTEM
Harmful vapors which may be formed within the engine
are removed from the crankcase, gear train, and valve
compartments by a continuous, automatic ventilating
system.
A slight pressure is maintained in the engine crankcase
by the seepage of a small amount of air from the air box
past the piston rings. This air sweeps up through the
flywheel housing, and is admitted to the valve
compartment through cavities in the lifter brackets.
Ventilating air in the valve compartment is drawn off via
the governor control housing (Fig. 1) or through a
breather attached to the side of the cylinder block (Fig.
Service
Inspect and clean the breather tube and breather and
Fig. 2 - Typical Breather Mounting
baffle if necessary to eliminate the possibility of clogging.
This can best be done by removing the breather tube
1.
Loosen the clamp and remove the breather cover.
from the governor and the breather and baffle from the
cylinder block, washing them with a suitable solvent and
2. Remove the four bolts and lock washers which
drying them with compressed air.
attach the breather adaptor to the oil pan adaptor and
remove the breather and gasket.
Clean the breather element (Fig. 3):
3. Loosen the bolt which fastens the element to the
breather body and remove the element and screen. Do
not lose the spring retaining clip which holds the bolt in
place.
4. Wash the element thoroughly in clean fuel oil and
dry it with compressed air.
5. Install the breather, using new gaskets, by reversing
the procedure for removal.
Fig. 1 - Typical Breather Pipe Mounting
Fig. 3 - Breather Mounting (Horizontal Engine)
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