18 32 050 Removing and installing/renewing catalytic converter cylinder 5-8 (N63)

Necessary preliminary tasks: 

• Remove UPPER HEAT SHIELD
• Remove monitoring sensor, cylinders 5-8  . See 11 78 540 REPLACING LEFT MONITOR SENSOR (N63) or 11 78 543 REPLACING RIGHT MONITOR SENSOR (N63)
• Remove REAR UNDERBODY PROTECTION .

F03 only: 

• Remove underbody protection on left and right

Picture shows the left side, the procedure for the right side is identical.

Release nuts (1) on left and right.

Tightening torque 18 31 1AZ .

Replace self-locking nuts.

Replace gaskets.

Fig 1: Identifying Exhaust System Nuts

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Unscrew nuts (1).

Tightening torque 18 20 1AZ .

Slacken nuts (2).

Lower exhaust system slightly towards the front.

Fig 2: Identifying Exhaust System And Slacken Nuts

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Release screws (1).

Remove left cable clip (2).

Fig 3: Identifying Cable Holders And Screws

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Release screw (1) on catalytic converter.

Tightening torque 18 32 4AZ .

Release clamp (2) on catalytic converter.

Replace clamp (2).

Tightening torque 18 32 1AZ .

Installation note: 

The clamp (2) must be installed with the screw toward the inside (illustration). Otherwise, the heat shield can no longer be installed on top.

Fig 4: Identifying Heat Shield, Screws And Clamps

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Installation note: 

The ends of the V-band clamps must rest parallel to each other.

Tightening torque 18 32 1AZ .

Fig 5: Identifying V-Band Clamps

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Installation note: 

If you can see a gap between the ends of the V-band clamps, release and then repeat the screw connection.

Tightening torque 18 32 1AZ .

Fig 6: Identifying Gap Between Ends Of V-Band Clamps

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Installation note: 

If the ends of the V-band clamps are positioned under each other, release and then repeat the screw connection.

Tightening torque 18 32 1AZ .

Fig 7: Locating V-Band Clamps Ends

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Release screw (1) from heat shields (2) and (3).

Screw (1) is located between the catalytic converters.

Fig 8: Identifying Catalytic Converters Screw

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Release screws (1) on left heat shield.

Unclip left heat shield and remove.

Fig 9: Identifying Screws On Left Heat Shield

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Release screw (1) on right heat shield.

Fig 10: Identifying Screw On Right Heat Shield

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Release screw (1) on heat shield at bottom right.

Unclip heat shield and remove.

Fig 11: Identifying Heat Shield Screw (Bottom Right)

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Release screws (1).

Detach hose (2) from cylinder head cover.

Release screws (3) on holder.

Tightening torque 18 32 2AZ .

Fig 12: Identifying Hose From Cylinder Head Cover And Screws

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Release screws (1) on catalytic converter, cylinders 5-8, rear, at cylinder head.

Tightening torque 18 32 3AZ .

Remove catalytic converter for cylinders 5-8.

Fig 13: Identifying Screws On Catalytic Converter

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Installation note: 

Picture shows the engine removed.

Replace gasket (1) on left exhaust turbocharger.

Fig 14: Identifying Turbocharger Gaskets

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Installation note: 

Clean sealing surfaces.

Replace gasket (1).

Fig 15: Identifying Gasket

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Assemble engine.

Check exhaust system for leaks.