Removing and installing cylinder head (S55 engine)

Special tools required:

11 7 170
11 8 580
11 0 320
11 0 000
11 9 000
11 4 430
11 4 471
11 4 472

IMPORTANT: Fit new cylinder head bolts.
Do not wash off bolt coating.
Lightly oil washer on the contact surfaces (both sides).
There must be no coolant, water or engine oil in the blind holes.
Risk of cracking and corrosion!

Necessary preliminary tasks:

Remove EXHAUST SYSTEM .
Remove both catalytic converters. Refer to REMOVING AND INSTALLING/REPLACE CATALYTIC CONVERTER FOR CYLINDERS 1-3 and REMOVING AND INSTALLING/REPLACE CATALYTIC CONVERTER FOR CYLINDERS 4-6 .
Drain COOLANT .
Drain ENGINE OIL .
Remove intake PLENUM .
Remove engine wiring harness. Refer to REMOVING AND INSTALLING/REPLACING WIRING HARNESS SECTION FOR ENGINE SENSOR SYSTEM MODULE 2 , REPLACING WIRING HARNESS SECTION FOR VALVETRONIC SERVOMOTOR , and REPLACING WIRING LOOM SECTION FOR IGNITION AND INJECTORS .
Remove RAIL .
Remove CYLINDER HEAD COVER .
Remove INTAKE AND EXHAUST CAMSHAFT ADJUSTERS .

Release screw (2).

Remove VANOS intake solenoid valve (1) with holder towards the front.

Release screw (3).

Remove VANOS solenoid valve, exhaust (4) with holder towards front.

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Release screws (1).

Detach coolant hose to cylinder head.

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Release ground strap (1) on cylinder head at rear.

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NOTE: Have a cleaning cloth ready to catch escaping engine oil.

Release screw (1) on oil filter module.

Release both engine oil pipes from thermostat.

Installation note:

Replace O-rings.

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Disconnect plug connection (1).

Unlock and detach coolant hose (2).

Unlock and detach coolant hose (3).

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Release screws (1).

Remove coolant pump.

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Release screws (1).

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Release nuts (1) on compressor inlet for exhaust turbochargers 1 to 3.

Detach clean air pipe and remove.

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Release screw (1) on heat shield.

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Release screw (1) on heat shield.

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Release screw (1) on heat shield.

Remove right ENGINE SUPPORT ARM .

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Release screw (1).

Release screw (2).

Detach oil return line (3) in direction of arrow.

Installation note:

Replace O-rings.

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Release screw (1).

Detach oil return line (2) in direction of arrow.

Installation note:

Replace O-rings.

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Release screw (1).

Release screw (2).

Detach oil feed line (3 and 4).

Installation note:

Replace O-rings.

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Release screw (1).

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Release screws (1).

Heat shield cannot be removed in the installed state.

Lay heat shield down loosely on exhaust turbocharger.

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Release screw (1).

Remove heat shield (2) towards top.

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Release screw (1).

Release coolant return line (2) from coolant thermostat.

Installation note:

Replace O-ring.

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Release screw (1).

Release coolant lines (2) from exhaust turbocharger.

Installation note:

Replace O-ring.

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Release screw (1).

Release screw (2).

Release coolant line (3) from exhaust turbocharger.

Installation note:

Replace O-ring.

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Remove coolant return line (1).

Lay down heat shield (2) loosely.

Installation note:

Replace O-ring.

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IMPORTANT: If the timing chain is stowed in the timing case, the crankshaft must no longer be rotated.

Release screws (1).

Unclip timing chain module (3) at separation point and lift out.

Release screw (2) for guide rail.

Set down timing chain.

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WARNING: There is a potential danger of injury by trapping fingers.

Intermediate shaft must be set to 90° position (center) to access the cylinder head bolt.

Adjust spindle drive (1) 4 mm using an Allen wrench to do so.

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Turn 4-mm hexagon socket wrench (1) clockwise in direction of arrow (maximum stroke).

Secure eccentric shaft with an open-end spanner (2) for support in direction of arrow.

Fix eccentric shaft with an open-end spanner (2) (kickback danger)

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Secure eccentric shaft (1) with special tool 11 7 170.

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Remove maximum stop (1).

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NOTE: Bolt (2) can only be released when the timing chain module is pressed forward slightly.

Release screws (1).

Tightening torque 11 12 3AZ .

Release screw (2).

Tightening torque 11 12 3AZ .

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Fig 1: Cylinder Head Bolts Tightening Sequence

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Release cylinder head bolts in sequence 14 to 1 with special tool 11 8 580.

NOTE: Graphic without intermediate lever and exhaust camshaft.

Secure special tool 11 0 320 with bolts (1).

Tightening torque 11 12 4AZ .

IMPORTANT: Removing and install cylinder head with a second person helping.
Weight of cylinder head with mounted parts approx. 55 kg.
Do not rest cylinder head on sealing surface.
Risk of damage to valves!