Suzuki Samurai 1986, Service Manual

Page: 157 / 482

POSITIVE CRANKCASE VENTILATION (PCV) SYSTEM
(Blow-by gas recycling system)
The blow-by gas in the crankcase flows through the passage in the cylinder block into the cylinder head.
The oil particles are separated from the blow-by gas by the oil separating unit in the cylinder head cover.
The gas is then returned together with the fresh air coming from the air cleaner through the PCV valve
into the intake manifold for recombustion.
When the vacuum in the intake manifold is low (when the opening of the throttle valve is large), the PCV
valve is wide open due to its spring force. Thus a large amount of the blow-by gas is drawn into the intake
manifold.
On the other hand, when the vacuum in the manifold is high, the PCV valve opening is limited due to the
high vacuum. Thus the amount of the blow-by gas drawn into the intake manifold is small.
Fresh air flow
Blow-by gas flow
Air cleaner case 6. PCV (Positive Crankcase Ventilation) valve
2. Air inlet’case 7. Cylinder head cover
3. Carburetor 8. Cylinder head
4. Intake manifold 9. Cylinder block
5. joint 10. Oil pan
Fig. 5-l-3 PCV system operation
5-5