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 41 020 Removing and installing/replacing starter motor (N52T)
No steel screws/bolts may be used due to the threat of electrochemical corrosion.
A magnesium crankcase requires aluminum screws/bolts exclusively.
Aluminum screws/bolts must be replaced each time they are released .
Aluminum screws/bolts are permitted with and without color coding (blue).
For reliable identification:
Aluminum screws/bolts are not magnetic .
Jointing torque and angle of rotation must be observed without fail (risk of damage) .
Necessary preliminary tasks:
- Switch off ignition.
- Disconnect BATTERY NEGATIVE LEAD .
- Remove INTAKE PLENUM .
Unlock connector (1) and remove.
Unfasten nut.
Tightening torque 12 42 2AZ .
Remove positive battery cable (2).
Release screw (1).
Installation note:
Replace aluminum screws .
Tightening torque 12 41 1AZ .
Unfasten screws (2).
Installation note:
Replace aluminum screws .
Tightening torque 12 41 2AZ .
Remove starter motor (3).
Installation note:
Check starter pinion and ring gear for damage. Replace starter motor if necessary.
Assemble engine.
Only during starter replacement and on vehicles with MSA (automatic engine start-stop function):
- Use BMW diagnosis system to reset the starter counter.
NO RELATED
Use the Manual With the Right Hardware
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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.