12 31 020 Removing and installing/replacing alternator (M57TU, M57T2)

Necessary preliminary work

Disconnect BATTERY EARTH LEAD .
Remove FAN COWL .
Remove . See 1128050 REMOVING AND INSTALLING/REPLACING DRIVE BELT (ELASTOBELT) FOR A/C COMPRESSOR (M57TU / M57T2) or 1128050 REMOVING AND INSTALLING/REPLACING THE DRIVE BELT (ELASTOBELT) FOR THE AIR CONDITIONING COMPRESSOR (M57T2-SCR) A/C compressor drive belt.
Remove alternator DRIVE BELT .
Remove front ENGINE GUARD .
Remove left turbocharger hose.

Slacken nut (1).

Disconnect plug connection (2).

Installation note:

The positive power supply of the preheating control unit is also connected to terminal 30 of the alternator. This lead must be connected without fail, otherwise the preheating system will fail.

Fig 1: Identifying Nut And Plug Connection

Courtesy of BMW OF NORTH AMERICA, INC.

If fitted

Remove cover (1).

Release screw underneath.

Remove deflecting element (2).

Fig 2: Identifying Cover And Deflecting Element

Courtesy of BMW OF NORTH AMERICA, INC.

Release screw (1).

Remove deflecting element (2).

Release screws (3).

Remove alternator (4).

Installation note:

If the Dynamic Drive optional extra is fitted, the alternator must be removed towards the bottom.

Fig 3: Identifying Deflecting Element With Screw And Alternator With Screws

Courtesy of BMW OF NORTH AMERICA, INC.

IMPORTANT: Risk of damage to the cooling system.

Installation note:

Check function of DDE.