LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> BMW >> 1986 >> 635CSi Standard >> Repair and Diagnosis >> Engine Performance >> System >> PCV System >> Description & Operation
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Description & Operation

A sealed system is used which does not allow entry of fresh air into crankcase. Crankcase vapors and blow-by gases are drawn from the crankcase up into valve cover. Vapors and gases are then drawn through airflow meter and into the intake manifold for burning with the incoming air/fuel mixture. Running engine creates crankcase vacuum; being a sealed system, no gases or vapors escape into atmosphere.

Fig 1: Crankcase Ventilation System (325, 325e, 325es & 528e)
G37819
Fig 2: Crankcase Ventilation System (535i, 635CSi, 735i & L7)
G37820