Overhaul

11 21 505 Sealing crankcase lower section (N51)

Special tools required:





Important!
Aluminum-magnesium materials.
No steel screws/bolts may be used due to the threat of electrochemical corrosion.
A magnesium crankcase requires aluminum screws/bolts exclusively.
Aluminum screws/bolts must be replaced each time they are released.
Aluminum screws/bolts are permitted with and without color coding (blue).
For reliable identification:
Aluminum screws/bolts are not magnetic.
Risk of damage!
Joining torque and angle of rotation must be observed without fail.





Important!
Changed procedure.
It is not necessary to remove the cylinder head and the crankshaft.

Necessary preliminary tasks:
^ Remove engine.
^ Mount engine on assembly stand.





^ Remove clutch (if fitted).
^ Remove left and right engine support arm
^ Remove oil sump.





Release screws (1).

Pull out oil pump intake pipe (2).

Tightening torque: 11 41 1AZ





Release screws (1).

Tightening torque: 11 13 5AZ.

Installation:
Replace aluminum screws.

Remove oil deflector (2).





Secure oil pump sprocket with steel pin diameter 6.0 mm (3) to oil pump.

Important!
Release central bolt (2) only together with steel pin diameter 6.0 mm (3).
Do not remove sprocket.

Release central bolt (2).

Tightening torque: 11 41 4AZ.

Unfasten screws (2).

Tightening torque: 11 41 5AZ.

Installation:
Replace aluminum screws.








Remove screw plug (1) from crankcase at front.

Note:
Replace gasket.





Release screw (1) for oil pump triangular drive with special tool 11 8 640.

Note:
It is not necessary to remove the triangular drive.





Version 1:
Attention!

Observe different screw lengths.

Release screws (1).

Tightening torque 11 41 2AZ.

Tightening torque 11 41 2AZ.

Installation:
Replace aluminum screws.

Version 2:
Attention!

Observe different screw lengths.

Release oil pump screws (1).

Tightening torque: 11 41 2AZ.





Installation:
Replace aluminum screws.





Detach sprocket (1) in direction of arrow.

Note:
The chain tensioner pushes the timing chain (3) of the triangular drive upward.

Do not remove camshaft sprocket.

Remove oil pump (2) in direction of arrow.





Installation:
Check spacer bushings (1) for secure seating and damage; replace if necessary.

Align twin surface (3) on oil pump (2) to sprocket wheel.

Install oil pump (2).





Note:
The special tool bore for the TDC position is located on the inlet side underneath the starter motor.

Rotate engine at central bolt and secure flywheel in position with special tool 11 0 300.

Secure flywheel with special tool (1) 11 9 260 and special tool (2) 11 9 266.

Tightening torque

Note:
Make sure that the special tool (1) completely engages in the flywheel teeth (see arrow)








Automatic transmission:
Release flywheel bolts (1).

Release special tool (2).

Remove flywheel (3).





Manual gearbox:

Important!
Position crankshaft at TDC.

Remove dual-mass flywheel.

Secure flywheel with special tool 11 9 260.

Remove vibration damper.

Release flywheel bolts with special tool 11 4 180





Release all crankcase bolts (1) along line (2).





Release crankcase bolts M10 in sequence 14 to 1.





Release crankcase lower section (1) from crankcase upper section (2) with suitable tool (3)

Remove crankcase lower section (1) upwards.

Important!
Do not rotate crankshaft without crankcase lower section (1) (risk of damage).





Important!
Timing chain is pre-tensioned.
Do not raise crankshaft.

Carefully remove radial shaft seal (1).

Catch escaping engine oil with a cloth (2).





Carefully remove radial shaft seal (1) towards front.

Catch escaping engine oil with a cloth (2).





Important!
Protect crankcase against sealant residues with a cloth (1).





Remove sealant residues (1) with special tool 11 4 470.

Remove injector nozzles (2) for liquid sealing compound on left and right.

Installation:
Replace injector nozzles (2).

Clean all threads with compressed air.





Position crankcase lower section (1) on crankcase upper section.

Screw in all M10 crankcase bolts.

Joint all M10 crankcase bolts (1) 20 Nm from inside outwards.

Identify all M10 crankcase bolts with a colored marking (1) for checking.








Secure crankcase bolts M10 in sequence 1 to 14 with special tool 00 9 120.

Tightening torque: 11 11 1AZ.





Insert all crankcase bolts (1).

Important!
Observe different lengths and sizes of the bolts.

Tightening torque: 11 11 2,3 and 4AZ.





Tighten screw (1) for oil pump triangular drive with special tool 11 8 640.

Note:
Replace screw.

Tightening torque: 11 41 3 AZ.

Tighten screw plug on front of crankcase.

Tightening torque: 11 11 8 AZ.

Installation:
Replace sealing ring.








Prepare radial shaft seal (1) on special tool 11 8 220.





Position radial shaft seal (1) with special tool 11 8 220 on the crankshaft.





Brush radial shaft seal (1) over the special tool 11 8 220.

Move radial shaft seal (1) parallel up against the crankcase.

Screw special tool 11 9 182 with screws (special tool 11 9 184 ) to crankshaft.








Installation:
Prepare special tool 11 9 181 for installation. Connect special tool 11 9 185 onto special tool 11 8 181.





Pull on radial shaft seal with special tool 11 9 181 and 11 9 185 in combination with special tool 11 9 183.





Screw on radial shaft seal with special tool 11 9 183 to limit position.

Installation:
Clean sealing surface (1) and degrease thoroughly in area of housing partition.

Apply a light coat of oil to running surface (2) of radial seal.

Note:





Graphic N42.





Push radial shaft seal (1) carefully in direction of arrow on the special tool 11 9 235.





Important!
Special tool 11 9 235 can only be attached with 2 opposite bolts.
Determine hole pattern on special tool.

Screw special tool 11 9 235 with special tool 11 9 234 on crankshaft.





Align groove (2) of radial shaft seal (1) centered to the housing partition (3.

Important!
After installation, the grooves must be filled with sealing compound.

Draw in radial seal with special tool 11 9 231 in conjunction with special tool 11 9 233 until flush.








Drive both injector nozzles (1) on left and right with special tool 11 9 360 into crankcase up to stop.





After fitting both sealing rings, check both sealing ducts for clearance.

Blow compressed air (1) at max. 6 bar into injector nozzle (2).

Compressed air must emerge at both sealing rings on left and right from the outlet bores.

Important!
If the compressed air does not flow out of all ducts. the crankcase must again be taken apart and cleaned.





Installation:
Use primer 1.3 and liquid seal 1.4.

Prepare liquid sealing compound (1) in special tool 11 4 370.

Injector nozzles for injecting sealing compound are not required.

Slowly insert liquid sealing compound (1) with special tool 11 4 370 in direction of arrow.

Liquid sealing compound must emerge at radial shaft seals at front and rear.








Stop (seal off) escaping liquid gasket with primer 1.3.





Stop (seal off) escaping liquid gasket with primer 1.3.





Assemble engine.

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