DETROIT DIESEL 53
4.8
VENTILATING SYSTEM
Harmful vapors which may be formed within the engine are removed from the crankcase, gear train and, valve
compartment by a continuous, pressurized ventilating system. A slight pressure is maintained in the engine crankcase
by the seepage of a' small amount of air from the airbox past the piston rings. This air sweeps up through the engine and
is drawn off through a crankcase breather. In-line engines are equipped with a breather assembly attached to the valve
rocker cover (Fig. I) or a breather assembly mounted on the flywheel housing (Fig. 2).
Fig. 1 - Typical Crankcase Breather Mounting (In-Line Engine)
Service
It is recommended that the breather tube be inspected and cleaned, if necessary, to eliminate the possibility of clogging.
This can best be done by removing the tube from the engine, washing it with a suitable solvent and drying it with
compressed air. The wire mesh pad (element) in the breather
Fig. 2 - Crankcase Breather Mounting and Details (In-Line Engine)
December, 1970 SEC. 4.8
Page 1
