If installed: Remove the silencer of the stationary heating

Remove the front section of the front wheel arch cover

NOTE: To provide a better overview: Schematic diagram with partially hidden components.

Remove screws (arrows).
Remove and extract front section (1) of the front wheel arch cover together with the brake ventilation duct (2).

Courtesy of BMW OF NORTH AMERICA, INC.
For replacement:
Loosen screw (1).

Remove brake ventilation duct (2).

Courtesy of BMW OF NORTH AMERICA, INC.

Remove the silencer of the stationary heating

Unscrew the nut (3) by 2 to 3 turns.
Detach the silencer (1) from the auxiliary heater.
Loosen screws (2).
Remove the silencer (1) from the auxiliary heater in the direction of the arrow.

Courtesy of BMW OF NORTH AMERICA, INC.