PCV System: Notes

The PCV system:

• uses intake manifold vacuum to ventilate blow-by vapors from the crankcase.
• returns the vapors to the intake manifold for combustion.

The PCV system consists of the:

• crankcase ventilation tube.
• PCV valve.

The PCV valve:

• varies the amount of blow-by vapors returned to the intake manifold based on available engine vacuum.
• prevents combustion gases backfiring into the crankcase.