18 32 050 Removing And Installing/Replacing Catalytic Exhaust Gas Converter, Cylinders 1-4 (N63)

Necessary preliminary tasks: 

• Remove acoustic cover by raising cover in upward direction.
Fig 1: Removing Acoustic Cover
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• Remove both intake filter housings  . See 13 71 030 REMOVING AND INSTALLING BOTH INTAKE FILTER HOUSINGS (N63) .
• Remove exhaust system  . See 18 00 020 REMOVING AND INSTALLING COMPLETE EXHAUST SYSTEM (N63) .
• Remove both connecting pipes  . See 18 32 605 REMOVING AND INSTALLING/REPLACING BOTH CONNECTING PIPES ON CATALYTIC CONVERTER (N63) .
• Remove both control sensors  . See 11 78 533 REPLACING RIGHT CONTROL SENSOR (N63) and 11 78 530 REPLACING LEFT CONTROL SENSOR (N63) .
• Remove both monitor sensors  . See 11 78 540 REPLACING LEFT MONITOR SENSOR (N63) and 11 78 543 REPLACING RIGHT MONITOR SENSOR (N63) .

Picture shows the left side, carry out the operation for the right side in an identical way.

Release screws (1).

Remove cable holders on left and right.

Fig 2: Identifying Cable Holders And Screws

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Remove rubber mounts (1) and release screws underneath.

Tightening torque. See 13 71 5AZ in 13 71 AIR INTAKE DUCT .

Remove cable holder (2).

Remove heat shield  (3) at top. See 11 65 180 REMOVING AND INSTALLING/REPLACING HEAT SHIELD AT TOP (N63) .

Fig 3: Identifying Rubber Mounts And Cable Holder

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Remove heat shield (1) at rear left and right.

This is described further below in the instruction.

Release screws (2) on catalytic converter.

Tightening torque. See 18 32 4AZ in 18 32 CATALYTIC EXHAUST GAS CONVERTER .

Release clamps (3) on catalytic converter.

Replace clamps (3).

Tightening torque. See 18 32 1AZ in 18 32 CATALYTIC EXHAUST GAS CONVERTER .

Installation: 

Clamps must be fitted with the screws pointing inwards (shown in picture). Otherwise it will not be possible to install the heat shield at the top.

Fig 4: Identifying Catalytic Converter Clamps And Screw

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Installation: 

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

Tightening torque. See 18 32 1AZ in 18 32 CATALYTIC EXHAUST GAS CONVERTER .

Fig 5: Identifying V-Band Clamps

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Installation: 

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

Tightening torque. See 18 32 1AZ in 18 32 CATALYTIC EXHAUST GAS CONVERTER .

Fig 6: Tightening V-Band Clamps

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Installation: 

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

Tightening torque. See 18 32 1AZ in 18 32 CATALYTIC EXHAUST GAS CONVERTER .

Fig 7: Locating V-Band Clamps

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

Screw (1) is located between catalytic exhaust-gas converters.

Fig 8: Identifying Heat Shields And Screw

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Release screws (1) on left heat shield.

Unclip left heat shield and remove.

Fig 9: Identifying Left Heat Shield And Screws

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Fig 10: Identifying Right Heat Shield And Screw

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Fig 11: Identifying Heat Shield And Screw

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Picture shows the left side, carry out the operation for the right side in an identical way.

Release screws (1).

Detach hose (2) from cylinder head cover.

Release screws (3) on holder.

Tightening torque. See 18 32 2AZ in 18 32 CATALYTIC EXHAUST GAS CONVERTER .

Fig 12: Identifying Cylinder Head Cover Hose And Screws

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Fig 13: Identifying Catalytic Converter And Screw

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

Tightening torque. See 18 32 3AZ in 18 32 CATALYTIC EXHAUST GAS CONVERTER .

Fig 14: Identifying Catalytic Converter And Screws

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1. Remove catalytic converter for cylinders 5-8 (1).
2. Remove catalytic converter for cylinders 1-4 (2).

Fig 15: Identifying Catalytic Converter

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Installation: 

Picture shows the engine removed.

Replace gaskets (1) on turbocharger.

Fig 16: Identifying Turbocharger

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Assemble engine.

Check exhaust system for leaks.