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12 31 020 Removing And Installing/Replacing Alternator (S54)

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NOTE: Switch off ignition. Follow instructions for disconnecting and connecting battery. Refer to 12 00 ... INSTRUCTIONS FOR DISCONNECTING AND CONNECTING BATTERY . Disconnect and cover battery negative lead.
CAUTION: When working on the oil, coolant or fuel circuit, it is essential to protect the alternator against contamination. Cover alternator with suitable materials. Failure to comply with this procedure may result in an alternator malfunction.

Remove fan cowl. Refer to 17 11 031 REPLACING FAN COWL (S54) .

Remove alternator drive belt. Refer to 11 28 010 REPLACING ALTERNATOR DRIVE BELT (S54) .

NOTE: Drain the main flow oil filter in order to prevent an excessive discharge of oil when the oil cooler lines are disconnected. This operation is described in 00 00 250 BMW ENGINE OIL SERVICE INCL. SUPPLEMENTARY SERVICE (S54) .

Release screw on holder for oil cooler lines (1).

Fig 1: Locating Screw Of Holder For Oil Cooler Lines
G03118152Courtesy of BMW OF NORTH AMERICA, INC.
CAUTION: Have a cleaning cloth ready. A small quantity of oil will emerge after the oil lines have been disconnected. Make sure no oil runs onto the alternator. Remove any remnants of oil immediately with cleaning cloth.
Fig 2: Identifying Oil Lines Retaining Screw
G03118153Courtesy of BMW OF NORTH AMERICA, INC.

Release screw.

Detach oil lines from main flow oil filter housing.

Lay oil lines to one side to open up access to screw connection of battery positive lead on alternator.

Installation: 

Replace O-rings.

Release nut (1).

Installation: 

Tightening torque, refer to 12 31 1AZ in ENGINE ELECTRICAL SYSTEM - TIGHTENING TORQUES .

Remove battery positive lead from alternator.

Unlock plug (2) and detach from alternator.

Fig 3: Unlocking Plug And Detaching From Alternator
G03118154Courtesy of BMW OF NORTH AMERICA, INC.

Release screw (1).

Lift off protective cap of screw (2) of tensioning roller.

Release screw (2) and pull out together with tensioning roller.

Remove alternator.

Fig 4: Removing Alternator
G03118155Courtesy of BMW OF NORTH AMERICA, INC.

Installation: 

Turning lock of tensioning roller must snap into place in groove.

Fig 5: View Of Tensioning Roller
G03118156Courtesy of BMW OF NORTH AMERICA, INC.
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