Removal and Replacement
11 12 100 Removing and installing cylinder head (N54, N54T)Special tools required:
Important!
Aluminium screws/bolts must be replaced each time they are released.
Aluminium screws/bolts are permitted with and without colour coding (blue).
For reliable identification:
Aluminium screws/bolts are not magnetic.
Jointing torque and angle of rotation must be observed without fail (risk of damage).
Necessary preliminary tasks:
^ Remove engine
^ Remove intake and exhaust camshaft adjusters
Release screws (1).
Unclip timing chain module (3) at junction (2) and remove towards top.
Set down timing chain.
Important!
If the timing chain is stowed in the gear case, the crankshaft must no longer be rotated.
This would cause the timing chain on the crankshaft sprocket to jam or jump.
Installation note:
The timing chain is lifted out with a hook only during assembly.
Note:
The lowest screw can only be released when the timing chain module is pressed forward slightly.
Important!
Secure the lowest screw with a gripper against falling down.
Release screws (1).
Tightening torque 11 12 3AZ.
Important!
Observe different bolt heads.
Release cylinder head bolts (1) M9 with special tool 11 4 420.
Tightening torque 11 12 2AZ.
Release cylinder head bolts (1) M10 with special tool 11 8 580 from outside inwards.
Tightening torque 11 12 1AZ.
Important!
All cylinder head bolts must be replaced.
Risk of damage!
Jointing torque and angle of rotation must be observed without fail.
Washers (1) of cylinder head bolts can only be removed with a magnet (2) between cylinder head and bearing strip.
Secure special tool 11 0 320 with existing cylinder head cover bolts (1).
Tightening torque 11 12 4AZ.
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 set cylinder head down on sealing face, risk of damage to valves.
Important!
Set down cylinder head with intake and exhaust camshafts on side only, risk of damage to valves (1).
Insert 11 4 430 special tool into bore holes.
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.
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 fluids or contaminants in any of the threaded holes (1) for the cylinder head bolt connections.
Risk of cracking and corrosion!
Clean all threaded holes.
Installation note:
Replace cylinder head gasket.
Important!
Observe sequence for tightening cylinder head bolts without fail.
Installation note:
Fit new cylinder head screws.
Insert cylinder head bolts (1 to 10) with special tool 11 8 580.
Tightening torque 11 12 1AZ.
Insert cylinder head bolts (11 to 14) with special tool 11 4 420.
Tightening torque 11 12 2AZ.
Note:
Graphic shows intake and exhaust camshafts removed.
Observe sequence for tightening cylinder head bolts without fail.
Important!
The 2nd angle of rotation relates only to cylinder head bolts 1 to 10.
Installation note:
^ Jointing torque:
All cylinder head bolts 1 to 14 to 30 Nm
^ 1st angle of rotation:
All cylinder head bolts 1 to 14 to 90°
^ 2nd angle of rotation:
Only cylinder head bolts 1 to 10 to 90°
^ 3rd angle of rotation:
All cylinder head bolts 1 to 14 to 45°
Installation note:
Replace screws (1).
Tightening torque 11 12 3AZ.
Important!
Secure the lowest screw with a gripper against falling down.
Assemble engine.
