11 12 100 Removing and installing/sealing cylinder head (N51)

Special tools required: 

• 11 0 320
• 11 4 420
• 11 4 430
• 11 4 471
• 11 4 472
• 11 8 580

Necessary preliminary tasks: 

• Remove exhaust system.
• Drain Coolant
• Drain off Engine Oil
• Remove both exhaust manifolds
• Remove Intake Air Manifold 
• Detach coolant hoses from cylinder head
• Remove Cylinder Head Cover. 
• Remove Intake And Exhaust Adjustment Unit 

Release screws (1).

Unclip timing chain module (2) at junction (3) and remove towards top.

Do not allow timing chain to drop down.

Installation: 

Only during assembly is the timing chain lifted out with a hook.

Fig 1: Timing Chain Module, Junction And Screw

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Unfasten screws (2).

Remove eccentric shaft sensor (1) towards front.

Fig 2: Bolts, Eccentric Shaft Sensor And Removal Direction

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Release screw (1).

Remove magnet wheel (2) towards front.

Fig 3: Magnet Wheel, Screw And Removal Direction

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Fig 4: Placing Magnet Wheel In Plastic Bag

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Pretension eccentric shaft (1) upwards in direction of arrow.

Remove stop screw between 1st and 2nd cylinders.

For tightening torque refer to 11 37 5AZ in 11 37 VARIABLE VALVE GEAR .

Fig 5: Eccentric Shaft And Pretensioning Directions

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Release screws (1).

For tightening torque refer to 11 12 3AZ in 11 12 CYLINDER HEAD WITH COVER (1AZ-12AZ) [N51] .

Screw (2) can only be released when the chain module is pressed forward slightly.

Fig 6: Timing Chain Module Bolt And Screw

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M 10 screw (1) is released with special tool 11 8 580.

M 9 screw (2) is released with special tool 11 4 420.

Fig 7: Special Tool (11 8 580), (11 4 420), M10 And M9 Cylinder Head Bolts

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Release screws (1 and 3) with special tool 11 4 420.

For tightening torque refer to 11 12 2AZ in 11 12 CYLINDER HEAD WITH COVER (1AZ-12AZ) [N51] .

Release screws (2) with special tool 11 8 580 from outside inwards.

For tightening torque refer to 11 12 1AZ in 11 12 CYLINDER HEAD WITH COVER (1AZ-12AZ) [N51] .

Fig 8: Cylinder Head Screws

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Secure special tool 11 0 320 with old cylinder head cover bolts (1).

For tightening torque refer to 11 12 5AZ in 11 12 CYLINDER HEAD WITH COVER (1AZ-12AZ) [N51] .

Fig 9: Special Tool (11 0 320) And Cylinder Head Cover Bolts

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Insert special tool 11 4 430 into bores.

Fig 10: Special Tool (11 4 430)

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Use special tool 11 4 471 to remove coarse gasket remnants from sealing faces of cylinder head and crankcase.

Fig 11: Special Tool (11 4 471)

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Remove fine gasket remnants with special tool 11 4 472.

Clean all pocket holes.

Replace Cylinder Head Gasket. 

Fig 12: Special Tool (11 4 472)

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Fit new cylinder head screws.

Insert screws (1 to 10) with special tool 11 5 190.

For tightening torque refer to 11 12 1AZ in 11 12 CYLINDER HEAD WITH COVER (1AZ-12AZ) [N51] .

Insert cylinder head bolts (11 to 14) with special tool 11 4 420.

For tightening torque refer to 11 12 2AZ in 11 12 CYLINDER HEAD WITH COVER (1AZ-12AZ) [N51] .

Fig 13: Cylinder Head Bolts Tightening/Loosening Sequence

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Observe tightening sequence. 

Installation: 

• Jointing torque:
  1. Angle of rotation: Screws 1 to 14 / 1x 90°
  2. Angle of rotation: Screws 1 to 10 / 1x 90°
  3. Angle of rotation: Screws 1 to 14 / 1x 45°

Replace screws (1).

For tightening torque refer to 11 12 4AZ in 11 12 CYLINDER HEAD WITH COVER (1AZ-12AZ) [N51] .

Fig 14: Bolts

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Installation: 

Replace aluminium screws. 

Assemble engine.