BMW X5: 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 the aluminum block on the N54.

The N52KP and N51 engines are still using the head gasket that is familiar from N52.

Fig. 18: Identifying Head Gasket

Oil Pan Gasket

All of the new NG6 engine use the same oil pan gasket as introduced on the N52.

The oil pan gasket design is compatible with the N54, therefore it was not necessary to create an additional part.

Fig. 19: Identifying Oil Pan Gasket

Bedplate Sealing

The N54 continues to use the injected sealant method for the bedplate.

Crankshaft Drive Components

Crankshaft

The crankshaft on the N52KP and N51 remains a cast iron design. This crankshaft is carried over from the N52.

The additional torque generated by the N54 requires the use of a forged steel crankshaft.

Piston and Connecting Rods

Due to the design requirements of each of the new NG6 engines, the piston design is unique to each version. For instance, the N54 is turbocharged and direct injected and requires a piston which meets the design requirements for compression and mixture formation.

The N51 engine need a piston which has lower compression and meets the SULEV II requirements for emission compliancy.

The N52KP and N52 engines both use the same piston design.

The connecting rods on the new engines use a thicker beam design which has been in production on the N52 since 6/06. The N54 has a special connecting rod with M9 bolts instead of the M8 bolts on the other engines.

Torsional Vibration Damper

The vibration damper has been updated to improve the damping of first order vibrations. The damper is secured with new bolts and has a revised tightening procedure. The procedure differs from the N52 and should therefore not me mixed up. Damage to the belt drive can result from improper tightening procedures.

Intake Manifold

The plastic intake manifold from the N52 is carried over to the new NG6 engines. However, the 3-Stage DISA version of the intake manifold is only used on the "O" version (high output).

The current N51 engine is designated as a medium output "M" version at 230 hp and does not require the 3- stage DISA. The same applies to the "M" version of the N52KP engine as well.

There are small modifications to these intake manifolds due to the fact that the crankcase ventilation system has been updated.

As far as the N54 engine is concerned, the intake manifold is designed specifically for the turbocharging system. The N54 does not require DISA as turbocharging supplies the necessary torque increase when needed.

Fig. 20: Identifying 3-Stage DISA Intake Manifold

Fig. 21: Identifying Intake Manifold N54

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