11 12 100 Removing and installing cylinder head (N20)

WARNING: This page is about a different variant/trim than selected.

Special tools required:

11 0 320
11 4 420
11 4 430
11 4 471
11 4 472
11 8 580
11 7 170
2 318 428

WARNING: Risk of injury in event of incorrect use.

IMPORTANT: Improper handling. Risk of damage!

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 EXHAUST TURBOCHARGER with integrated exhaust manifold.
Drain COOLANT
Drain off ENGINE OIL
Remove intake PLENUM .
Detach coolant hoses from cylinder head
Remove INTAKE AND EXHAUST CAMSHAFT ADJUSTER
Remove INJECTOR SHAFTS .

IMPORTANT: Secure eccentric shaft (1) with open-end spanner (3) (risk of return stroke).

Slowly adjust eccentric shaft (1) to minimum lift via servomotor using 4-mm hexagon socket wrench (2) and open-end spanner (3).

Fig 1: Adjusting Eccentric Shaft Using Hexagon Socket Wrench And Open-End Spanner

Position eccentric shaft in the middle between maximum stroke and minimum stroke.

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

The open-end spanner can now be removed.

Fig 2: Securing Eccentric Shaft With Special Tool (11 7 170)

Remove maximum stroke limit position (2).

Tightening torque: 11 37 5AZ.

Fig 3: Identifying Cylinder Head Maximum Stroke Limit Position

Unclip engine wiring harness (1).

Release screw (1).

Remove bracket (3).

Fig 4: Locating Bracket, Engine Wiring Harness And Screw

Release bolts (1) from timing chain module on cylinder head.

Tightening torque 11 31 4AZ .

Remove upper chain module upwards.

Fig 5: Identifying Timing Chain Module Bolts

Remove VIBRATION DAMPER .

Open screw plug (2).

Tightening torque 11 11 7AZ .

Fig 6: Identifying Screw Plug

Release right bearing journal (1) from chain module for timing chain on crankcase.

Tightening torque 11 31 5AZ .

Fig 7: Identifying Bearing Journal

Press chain module slightly to one side.

Release screws (1).

Tightening torque 11 12 3AZ .

Fig 8: Identifying Screws

Release screw (1).

Tightening torque 11 12 3AZ .

Fig 9: Identifying Screw

Various special tools are required for the cylinder head screw connection.

Screw M11 with special tool 11 8 580

Screw M9 with special tool 11 4 420 (old)

Screw M9 with special tool 2 318 428 (new)

Fig 10: Installing Cylinder Head Screw Using Special Tool (11 8 580)

Fig 11: Cylinder Head Bolts Tightening/Loosening Sequence (N20, N26)

Release cylinder head bolts in sequence 10 to 7 with special tool 11 4 420 or 2 318 428 .

Release cylinder head bolts in sequence 6 to 1 with special tool 11 8 580 .

NOTE: Graphics show intermediate lever, intake and exhaust camshaft.

IMPORTANT: Removing and install cylinder head with a second person helping.

Weight of cylinder head with add-on parts is approx. 40 kg.

Do not rest cylinder head on sealing surface. Risk of damage to valves !

Remove coarse residues on sealing surfaces with special tool 11 4 471 from cylinder head and crankcase.

IMPORTANT: Do not use any metal-cutting tools.

Fig 12: Removing Coarse Residues On Sealing Surfaces Using Special Tool (11 4 471)

Remove fine residues on sealing surfaces with special tool 11 4 472 from cylinder head and crankcase.

IMPORTANT: Do not use any metal-cutting tools.
There must be no coolant, water or engine oil in the pocket holes.
Risk of cracking and corrosion!

Fig 13: Removing Fine Residues On Sealing Surfaces Using Special Tool (11 4 472)

Clean all blind holes.

Replace CYLINDER HEAD GASKET .

Fig 14: Cylinder Head Bolts Tightening/Loosening Sequence (N20, N26)

Fit new cylinder head bolts.

Insert cylinder head bolts (1 to 6) with special tool 11 8 580 .

Tightening torque 11 12 1AZ .

Insert cylinder head bolts (7 to 10) with special tool 11 4 420 or 2 318 428 .

Tightening torque 11 12 2AZ .

Insert bolts (1).

Tightening torque 11 12 3AZ .

Fig 15: Identifying Bolts

Insert screw (1).

Tightening torque 11 12 3AZ .

Fig 16: Identifying Screw

Assemble engine.