18 32 050 Removing and installing/renewing catalytic converters for cylinders 1-4 (S63B44 T 0)

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

Necessary preliminary tasks:

Release screw (1).

Tightening torque 18 32 2AZ .

Unfasten screws (2).

Tightening torque 18 32 3AZ .

Remove bracket (3).

Unscrew nuts (4).

Tightening torque 18 32 4AZ .

Release screws (5).

Tightening torque 18 32 3AZ .

Remove holder (6).

Fig 1: Identifying Exhaust System Holder, Bracket Nut And Screws

Courtesy of BMW OF NORTH AMERICA, INC.

Release screw (3).

Tightening torque 18 32 1AZ .

Remove and replace clamp (4).

Remove catalytic converters for cylinders 1-4 upward.

Installation note:

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

Fig 2: 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 3: 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 4: 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 5: Locating V-Band Clamps Ends

Courtesy of BMW OF NORTH AMERICA, INC.

Assemble engine.

Check exhaust system for leaks.