18 32 050 Removing and Replacing the Catalytic Converter Cylinders 1-4

18 32 050 Removing and installing/replacing catalytic exhausts gas converter, cylinders 1-4 (N63 hybrid)






Warning!
High-voltage system - danger to life!






Warning!
The following points must be strictly observed prior to starting work:
- De-energise the high-voltage system
- Observe safety instructions for handling with hybrid vehicles






Warning!
Scalding hazard!
Only perform these tasks on an engine that has cooled down.






Necessary preliminary tasks:
- Remove heat shield
- Remove both intake filter housings
- Remove exhaust system
- Remove both connecting pipes
- Remove both control sensors
- Remove both monitor sensors






Unscrew nuts (1).
Tightening torque 18 32 5AZ.
Release holders (2) and (3) for high-voltage line and lay to one side.






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.






Remove rubber mounts (1) and release screws underneath.
Tightening torque 13 71 5AZ.
Remove cable holder (2).
Remove heat shield (3) at top.






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 18 32 4AZ.
Release clamps (3) on catalytic converter.
Replace clamps (3).
Tightening torque 18 32 1AZ.

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.






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

Tightening torque 18 32 1AZ.






Installation:
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.






Installation:
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.






Release screw (1) from heat shields (2) and (3).
Screw (1) is located between catalytic exhaust-gas converters.






Note:
Picture shows the engine removed.

Release screws (1) on left heat shield.
Unclip left heat shield and remove.






Note:
Picture shows the engine removed.

Release screw (1) on right heat shield.






Note:
Picture shows the engine removed.

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






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 18 32 2AZ.






Note:
Picture shows the engine removed.

Release screws (1) on catalytic converter, cylinders 1--4, rear, at cylinder head.
Tightening torque 18 32 3AZ.






Note:
Picture shows the engine removed.

Release screws (1) on catalytic converter, cylinders 5--8, rear, at cylinder head.
Tightening torque 18 32 3AZ.






Note:
To remove the catalytic converter for cylinders 1--4, it is necessary to remove the catalytic converter for cylinders 5--8.

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






Installation:
Picture shows the engine removed.

Replace gaskets (1) on turbocharger.






Assemble engine.
Check exhaust system for leaks.