Mazda 323 1988 Workshop Manual page 256

4A
POSITIVE CRANKCASE VENTILATION (PCV) SYSTEM
POSITIVE CRANKCASE VENTILATION (PCVI SYSTEM
Cylinder head ccwer
+ Clean air
- Blowby gas
The PCV valve is operated by intake manifold vacuum to prevent blow-by gas from escaping to the
atmosphere. When the engine is running at idle, the PCV valve is slightly opened and small amount
of blow-by gas is drawn into the dynamic chamber.
At high engine speed, the PCV valve is further opened and large amount of blow-by gas; drawn into
the dynamic chamber.
PCV VALVE
Inspection
1. Warm up the engine to the normal operating tem-
perature and run it at idle speed.
2. Disconnect the PCV valve with the ventilation hose
from the cylinder head cover.
3. Block the PCV valve opening by finger.
If the engine speed drops, the PCV valve is work-
ing properly.
4A--56