Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
12 31 Alternator with Drive and Mounting Parts
2009 BMW 550i AutomaticSECTION 12 31 Alternator with Drive and Mounting Parts
ALTERNATOR WITH DRIVE AND MOUNTING PARTS - TIGHTENING TORQUE SPECIFICATION
| Type | Thread | Tightening specification | Measure | |
|---|---|---|---|---|
| 1AZ Wires to alternator | ||||
| Terminal D+ | M10 / M20 | 5 Nm | ||
| All / others | M6 | 7 Nm | ||
| Terminal B+ | S38 / B38 | 8 Nm | ||
| All / others | M8 | 13 Nm | ||
| 2AZ Pulley | All | 45 Nm | ||
| 3AZ Pulley (ribbed drive belt) | Alternator with cooling jacket | 80 Nm | ||
| all others | 70 Nm | |||
| N42, N46 Valeo | 75 Nm | |||
| N42, N46 Bosch | 65 Nm | |||
| 4AZ Rear holder | All | 3.5 Nm | ||
| 5AZ Fillister head screw for wire holder | All | 3.5 Nm | ||
| 6AZ Alternator on bearing block | M40/M42 / M43 / M44 | 43 Nm | ||
| 7AZ Alternator to crankcase | N42, N46, N62 | M8 | 21 Nm | |
| 8AZ Belt pulley (ribbed V-belt) with freewheel (Ina) fitted to Bosch and Valeo alternators | N42, N43 | 80 Nm |
RENDER: 1.0x
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.