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

18 32 050 Removing and Replacing The Catalytic Converter Cylinder 1-4 (N63)







WARNING:
Risk of burning.
Only perform this repair work on an engine that has cooled down.







Necessary preliminary work:
- Remove acoustic cover
- Remove both intake silencer housings.
- Remove exhaust system.
- Remove both control sensors.
- Remove both monitoring sensors.







Picture shows the left side, carry out the operation for the right side in an identical way.
Release screws (1).
Remove cable clips on left and right.







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







Remove heat shield (1) at rear left and right.
This is described further below in the instructions.
Release screws (2) on catalytic converter.
Tightening torque 18 32 4AZ.
Loosen the clamps (3) from the catalytic converter.
Replace clamps (3).
Tightening torque 18 32 1AZ.

Installation note:
Clamps must be installed with the screws toward the inside (Figure). Otherwise, a top heat shield can no longer be installed.







Installation note:
The ends of the V-band clamps must rest parallel to each other.
Tightening torque 18 32 1AZ.







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.







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.







Release screw (1) from heat shields (2) and (3).
Screw (1) is located between the catalytic 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.

Loosen screws (1) on the catalytic converter cylinders 1-4 on the back of the 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 cylinders 1-4, it is necessary to remove the catalytic converter cylinders 5-8.

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







Installation note:
Picture shows the engine removed.
Replace the seals (1) on the exhaust turbocharger.







Installation note:
Picture shows the left side, the procedure for the right side is identical.
Clean sealing surfaces. Replace gasket (1).







Assemble engine.
Check exhaust system for leak tightness.