Removal and Replacement
11 12 100 Removing and installing cylinder head (N52K)Special tools required:
Important!
Aluminium-magnesium materials.
No steel screws/bolts may be used due to the threat of electrochemical corrosion.
A magnesium crankcase requires aluminium screws/bolts exclusively.
Aluminium screws/bolts must be replaced each time they are released.
Aluminium screws/bolts are permitted with and without color 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 exhaust system
^ Drain coolant
^ Drain off engine oil
^ Remove both exhaust manifolds
^ Remove intake plenum
^ Detach coolant hoses from cylinder head
^ Remove intake and exhaust camshaft adjusters
Important!
Fit new cylinder head screws.
Do not wash off bolt coating.
There must be no fluids or contaminants in any of the threaded holes for the cylinder head bolt connections.
Risk of corrosion and cracking!
Apply a light coat of oil to washer contact areas and threads of new cylinder head bolts.
Release screws (1).
Unclip timing chain module (2) at junction (3) 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 wheel to jam or jump.
Installation:
The timing chain is lifted out with a hook only during assembly.
Release bolts (2) for eccentric shaft sensor (1).
Remove eccentric shaft sensor (1) towards front.
Important!
Screw (1) is not magnetic and must be secured against falling down.
Release screw (1).
Remove magnet wheel (2) towards front.
Important!
Magnet wheel (1) is highly magnetic and must be protected against metal filings/borings.
After removing, place magnet wheel (1) in a plastic bag (2) with a seal.
Pre-tension eccentric shaft (1) upwards in direction of arrow.
Remove stop screw between 1st and 2nd cylinders.
Tightening torque 11 37 5AZ.
Note:
Bolt (2) can only be released when the timing chain module is pressed forward slightly.
Important!
Secure bolt (2) with a gripper against falling down.
Release screw (2).
Tightening torque 11 12 3AZ.
Release screws (1).
Tightening torque 11 12 4AZ.
Installation:
Replace aluminium screws.
Important!
Observe different bolt heads.
Release cylinder head bolts (1) M10 with special tool 11 8 580.
Release cylinder head bolts (2) M9 with special tool 11 4 420.
Note:
Picture shows intake and exhaust camshafts removed.
Important!
Observe different M9 bolt lengths (1 and 3).
Undo cylinder head bolts (1 and 3) M9 using special tool 11 4 420.
Tightening torque 11 12 2AZ.
Release cylinder head bolts (2) M10 with special tool 11 8 580 from outside inwards.
Tightening torque 11 12 1AZ.
Important!
All cylinder head bolts (1, 2 and 3) must be replaced.
Joining torque and angle of rotation must be observed without fail.
Risk of damage!
Secure special tool 11 0 320 with existing cylinder head cover bolts (1).
Tightening torque 11 12 5AZ.
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!
Insert 11 4 430 special tool into bores.
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 corrosion and cracking!
Clean all threaded holes.
Replace cylinder head gasket.
Important!
Observe sequence for tightening cylinder head bolts without fail.
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:
Picture shows intake and exhaust camshafts removed.
Observe sequence for tightening cylinder head bolts without fail.
Important!
The 2nd torsion angle relates only to cylinder head bolts 1 to 10.
Installation:
^ 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°
Insert bolts (1).
Tightening torque 11 12 4AZ.
Important!
Secure bolt (2) with a gripper against falling down.
Insert bolt (2).
Tightening torque 11 12 3AZ.
Installation:
Replace aluminium screws.
Assemble engine.
�wK:
