18 32 050 Removing and installing/renewing catalytic converters for cylinders 1-4 (N63)

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

Necessary preliminary tasks:

Remove upper HEAT SHIELD .
Remove the UNITS COMPARTMENT PARTITION WALL .
Remove EXHAUST SYSTEM .
Remove VACUUM PUMP .
Remove the RIGHT MONITORING SENSOR .

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

Screw (1) is located between the catalytic converters.

Tightening torque 18 31 3AZ .

Fig 1: Identifying Heat Shields And Screw

Courtesy of BMW OF NORTH AMERICA, INC.

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

Tightening torque 18 31 3AZ .

Fig 2: Identifying Heat Shield Screw (Bottom Right)

Courtesy of BMW OF NORTH AMERICA, INC.

Release the screws (1) on the right heat shield.

Tightening torque 18 31 3AZ .

Unclip and remove the right heat shield.

Fig 3: Identifying Screws On Right Heat Shield

Courtesy of BMW OF NORTH AMERICA, INC.

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

Tightening torque 18 31 3AZ .

Fig 4: Identifying Heat Shield Screw (Bottom Left)

Courtesy of BMW OF NORTH AMERICA, INC.

Release screw (1) on right left shield.

Tightening torque 18 31 3AZ .

Unclip and remove the heat shield (2) on the left.

Fig 5: Identifying Screw On Right Left Shield

Courtesy of BMW OF NORTH AMERICA, INC.

Release screws (1).

Tightening torque 18 32 2AZ .

Fig 6: Identifying Screws

Courtesy of BMW OF NORTH AMERICA, INC.

Loosen screws (1) on the catalytic converter cylinders 1-4 on the back of the cylinder head.

Tightening torque 18 32 3AZ .

Fig 7: Identifying Screws On Catalytic Converter Cylinders 1-4

Courtesy of BMW OF NORTH AMERICA, INC.

NOTE: Graphic 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 .

Fig 8: Identifying Screws On Back

Courtesy of BMW OF NORTH AMERICA, INC.

Release screw (1) only.

Tightening torque 18 32 1AZ .

Remove and renew clamp (2) only.

Installation note:

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

Fig 9: Identifying Clamps And Screws

Courtesy of BMW OF NORTH AMERICA, INC.

Remove catalytic converter for cylinders 1- 4.

Replace gasket on exhaust turbocharger.

Installation note:

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

Tightening torque 18 32 1AZ .

Fig 10: Identifying V-Band Clamp Ends

Courtesy of BMW OF NORTH AMERICA, INC.

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 11: Identifying Gap Between Ends Of V-Band Clamps

Courtesy of BMW OF NORTH AMERICA, INC.

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 12: Identifying Misalignment Of V-Band Clamp Ends

Courtesy of BMW OF NORTH AMERICA, INC.

Assemble engine.

Check exhaust system for leak tightness.