12 31 020 Removing and installing or replacing alternator (N55)

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Necessary preliminary work:

Switch off ignition
Disconnect BATTERY EARTH LEAD and cover.
Remove front CHARGE-AIR DUCT .
Remove rear CHARGE-AIR DUCT .
Remove alternator DRIVE BELT .

NOTE: In order to remove the alternator, it is necessary to REMOVE the air conditioning compressor.
In so doing:

Do not draw off A/C system refrigerant.
Do not detach refrigerant lines from A/C compressor.
Do not remove air conditioning compressor; instead, release from bracket only and place to one side.

Release screws (1).

Tightening torque 12 31 1AZ .

Release screw (2).

Tightening torque 12 31 2AZ .

Release screw (3) and remove with holder (4).

Fig 1: Identifying Screws And Holder

Courtesy of BMW OF NORTH AMERICA, INC.

Tightening torque 12 31 2AZ .

Unlock connector (1) and remove.

Remove protective cap (2) and release nut underneath.

Tightening torque 12 42 1AZ .

Fig 2: Identifying Protective Cap And Connector

Courtesy of BMW OF NORTH AMERICA, INC.

Remove positive battery cable (3).

NOTE: For purposes of improved clarity, illustrations and description show A/C compressor removed.

Release screws (1) a few turns until bracket (2) is loose. Do not remove bracket (2).

Tightening torque 12 31 3AZ .

Feed out alternator (3) and remove.

Fig 3: Identifying Alternator, Screws And Bracket

Courtesy of BMW OF NORTH AMERICA, INC.

Assemble engine.