Daihatsu F300 Service Manual page 1343

EMISSION CONTROL SYSTEM
POSITIVE CRANKCASE VENTILATION (PCV)
To combat air-pollution problems, the engine is equipped with a sealed type positive crankcase ventilation
system in order to prevent blow-by gases generated inside the crankcase from being released into the
atmosphere.
The blow-by gases generated inside the crankcase flow into the cylinder head side through the gas passages
of the cylinder block.
When the throttle valve opening degree is small, first the oil in the blow-by gas is separated by the oil
separator provided at the cylinder head cover. Then, the blow-by gases flow from the carburetor heat insulator
section to the intake manifold. Thus, the gases are sucked into the cylinder and burned again.
At this time, fresh air flows from the upstream of the throttle valve ·Into the cyr1nder head cover. The air flow
rate is restricted by a jet located at the cylinder head cover, thus stabilizing the engine idling.
When the throttle valve opening degree is great and/or a large amount of blow-by gases are generated, the
blow-by gases flow through both the upstream and the downstream of the throttle valve and are sucked into
the combustion chamber.
Crankcase gas
Fresh air
HO.C engine
INSPECTION OF PCV HOSE & CONNECTION
Visual inspection of hoses and connection
Check the hoses for improper connections, cracks, leak or
damage.
Replace or repair any part which exhibits defects.
EC--4
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