BMW X5: Cylinder Head Cover
As stated before, the cylinder head cover used on all of the new NG6 engines is made from plastic. However, the design differs between the engines due to engine equipment.
For example, the N54 engine does not use Valvetronic and therefore does not need the accommodation for the VVT motor. Also, the crankcase ventilation system is different on the N54. Some of the crankcase venting components are integrated into the cylinder head cover such as the cyclone separator.
The N52KP and N51 engines have the same cylinder head cover. The cover also includes some of the crankcase venting system components.
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Fig. 13: Identifying Cylinder Head Cover
NOTE: Some engines with plastic cylinder head covers may have aluminum bolts.
Cylinder Head
Each of the new NG6 engines has a unique cylinder head design. Due to some of the technical requirements, the cylinder heads are not interchangeable between these engines. The cylinder head from the N52KP is carried over from the N52 with little change.
The cylinder head from the N54 engine does not have Valvetronic. The design of the engine also requires accommodation of the "direct" fuel injector in the combustion chamber. Most of the external dimensions are the same as the N52 to accommodate accessories and ancillary components.
The N51 engine is a SULEV II compliant design which has a lower compression ratio. The combustion chamber design has been modified to work in conjunction with the N51 piston to achieve the required emission goals.
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Fig. 14: Identifying Fuel Injector In Combustion Chamber
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Valvetrain
The valvetrain on the N52 introduced in 2006, used 5 mm valve stems on both
the intake and exhaust. To
increase durability, the exhaust valve stems were increased to 6 mm from 6/06
production.
All
Gaskets And Seals
Head Gasket
The head gasket design on the N54 is unique to that engine.
It features a multi-layer steel design. There is no silicone rubber perimeter
"shelf" as on the N52. This is not
needed due to
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 t
SEE MORE:
Replacing Upper Vent Line For Air Supply Unit
IMPORTANT: Risk of damage!
Extreme cleanliness must be ensured in the connection area of the vent lines
during removal and installation. Even the smallest of dirt particles can cause
leakage in the air spring system.
Necessary preliminary tasks:
Remove trim panel for cover on frame side member on
Fuel System Testing
Fuel systems need to be checked for proper fuel pressure as well as
sufficient volume. When diagnosing fuel
system complaints, you must take into account the type of fuel system and how
the fuel is delivered to the
engine.
Malfunctions in the fuel system can cause driveability complaints which in
