BMW X5: Crankcase Ventilation

One of the major changes on the new NG6 engines is that the crankcase ventilation system has been upgraded and improved. This applies to all of the new NG6 versions (N52KP, N51 and N54).

There are two distinct versions of crankcase ventilation. One type is unique to the N54 and the other applies to N51 and N52KP.

The N52, which is still in production continues to use the "external" crankcase ventilation system with the electrically heated crankcase ventilation valve/cyclone separator.

Fig. 22: Identifying Crankcase Ventilation System

Crankcase Ventilation (N51 and N52KP)

The crankcase ventilation system on the N51 and N52KP has been modified as compared to the N52. The system is integrated into the plastic cylinder head cover.

The crankcase gases are regulated by a crankcase ventilation valve similar to the design used on the N62. The crankcase vent valve is currently part of the cylinder head cover and is not replaceable as a separate component.

Oil separation is carried out via a "labyrinth" system and two cyclone separators which are incorporated into the cylinder head cover. By having the system components integrated into the cylinder head cover, the crankcase gases are heated by the engine rather than an electric heater as on the N52. However, there is still one electric heating element at the manifold inlet.

Once the liquid oil is separated from the crankcase vapors, the oil is allowed to drain back through check valves back into the engine.

Fig. 23: Cylinder Head Cover Components Location

Crankcase Ventilation (N54)

Since the N54 is a turbocharged engine, the crankcase ventilation system has to meet certain design requirements. For example, when the engine is in turbocharged mode, the increased manifold pressure should not have an adverse effect on the crankcase venting. This is why, there is no crankcase ventilation valve in the system.

The system consists of four small cyclone separators which are integrated into the plastic cylinder head cover.

The flow of crankcase gases is metered through a series of restrictions which control the ultimate crankcase pressure.

Fig. 24: Cyclone Separator Operation

One of the main operating principles behind the crankcase venting system on the N54 is that there are two strategies - one for the turbocharged mode and one for "non-turbocharged" operation such as decel. These strategies are dependent upon the intake manifold pressure.

Fig. 25: Cutaway View - Cylinder Head

Crankcase Ventilation System Overview (N54)

Fig. 26: Identifying Crankcase Ventilation System Diagram - Decel Mode

Crankcase Ventilation System Overview (N54)

Fig. 27: Identifying Crankcase Ventilation System Diagram - Turbocharged Model

CRANKCASE VENTILATION COMPONENTS INDEX

Fig. 28: Identifying Charge Air Suction Pipe

Name the components above and their purpose:

Summary of Mechanical Changes

SUMMARY OF MECHANICAL CHANGES

MSD80 ENGINE MANAGEMENT OVERVIEW (E9X)

Fig. 29: Identifying Engine Management Communication Diagram - E9X (1 Of 2)

Fig. 30: Identifying Engine Management Communication Diagram - E9X (2 Of 2)

MSV80 ENGINE MANAGEMENT OVERVIEW (E70)

Fig. 32: Identifying Engine Management Communication Diagram - E70 (2 Of 2)

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