SSANGYONG 1999 Musso Service Manual page 207

1B2-18 M161 ENGINE MECHANICAL
Operation at Idling and Mid-Load
The throttle valve(6) is closed or very partially opened, and
the vacuum pressure in intake manifold is high.
The blow-by gas and the fresh air that is additionally supplied
through the vent connection(D) in the crankcase in partial
load gets supplied to the combustion chamber from the crank
chamber(12) through the oil separation chamber(11), air-
conditioner bracket(10), vent line(9), and restrictor(7)
mounted to the cylinder head.
The circulated engine oil returns to the oil pan through the
oil return pipe(13) at the bottom of oil separation
chamber(11).
The fresh air gets supplied to the crank chamber(12) through
the HFM sensor(1), intake air duct(4), vent line(5), oil
separation chamber(3), chain housing(17), and the timing
gear case cover(15).
The additional supply of the fresh air is needed to prevent
from forming the residues of the engine oil.