1.9 Positive Crankcase Ventilation (PCV) System

The PCV architecture of the turbo charged new 8-cylinder engine N63 is designed as a two way ventilation system. This two-way ventilation system is designed with two separate connections between the crankcase and the intake manifold.

Connection (1) is used at part load and ends after the turbo charger in the intake manifold. The PCV Valve used in this path is fastened directly onto the crankcase. A disconnection or leakage in this part of the PCV system is indicated by a rough or stalling engine and results in a reaction in the fuel system (fuel trim deviation) or in the misfire system. A fault code is stored in both cases.

Part load: 

Fig 1: Positive Crankcase Ventilation - System Diagram (Part Load)

Courtesy of BMW OF NORTH AMERICA, INC.

Connection (2) is used at high load and ends before the turbo charger in the intake manifold. The end of the line, which is fixed to the crank case, including a separate check valve, cannot be disconnected without demolishing the parts affected. The connection fixed onto the air duct can be removed.

A disconnection in this end of the line is indicated by a rough or stalling engine and results in a reaction within the fuel system (fuel trim deviation), air mass flow plausibility, or misfire system. A fault code is stored in all of the cases listed above.

Full load: 

Fig 2: Positive Crankcase Ventilation - System Diagram (Full Load)

Courtesy of BMW OF NORTH AMERICA, INC.