Crankcase Ventilation Systems: Description

NOTE: Diesel Pickup models do not use a PCV system.

The crankcase ventilation system is designed to return blow-by gases to engine, through intake manifold and air cleaner. Gasoline models use a PCV valve to control blow-by flow, while diesel models have a crankcase emission control valve to perform the same function.

Fig 1: Datsun Crankcase Ventilation System (Gasoline Maxima & Non-Turbo 280ZX Models)

Courtesy of NISSAN NORTH AMERICA, INC.

Note direction of flow.