18 32 050 Removing and installing/renewing catalytic converters for cylinders 1-4 (N63 B40/B44 O 1)

Necessary preliminary tasks: 

• Remove upper HEAT SHIELD .
• Remove the front bulkhead SOUND INSULATION .
• 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.

Fig 1: Identifying Catalytic Converters Screw

Courtesy of BMW OF NORTH AMERICA, INC.

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

Fig 2: Identifying Heat Shield Screw (Bottom Right)

Courtesy of BMW OF NORTH AMERICA, INC.

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

Unclip and remove the right heat shield.

Fig 3: Identifying Right Heat Shield Screws

Courtesy of BMW OF NORTH AMERICA, INC.

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

Fig 4: Identifying Heat Shield Screws (Bottom Left)

Courtesy of BMW OF NORTH AMERICA, INC.

Release screw (1) on right left shield.

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

Fig 5: Identifying Right Left Shield Screw

Courtesy of BMW OF NORTH AMERICA, INC.

Release screws (1).

Tightening torque 18 32 2AZ .

Fig 6: Identifying Catalytic Converter 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 Catalytic Converter Screws Cylinders 1-4

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 8: Identifying Screws On Catalytic Converter Cylinders 1-4 On Back Of Cylinder Head

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 (Figure). Otherwise, a top heat shield can no longer be installed.

Remove catalytic converter for cylinders 1-4.

Replace gasket on exhaust turbocharger.

Fig 9: Identifying Catalytic Converter, Clamp And Screw

Courtesy of BMW OF NORTH AMERICA, INC.

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 Clamps

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: Locating V-Band Clamps Ends

Courtesy of BMW OF NORTH AMERICA, INC.

Assemble engine.

Check exhaust system for leaks.