2021 BMW M3

The 2021 BMW M3 (G80) marked the return of the iconic sports sedan. It features a 3.0-liter twin-turbocharged inline-six engine, known as the S58, producing 473 horsepower and 406 lb-ft of torque in the base model, and 503 horsepower and 479 lb-ft of torque in the Competition variant. A six-speed manual transmission was available on the base model, while an eight-speed automatic transmission was standard on the Competition. People generally praise the M3 for its exceptional performance, handling, and driver engagement, while some criticize its controversial styling and the lack of steering feel compared to previous generations.

Engine

S58 3.0L Twin-Turbo Inline-Six (Base and Competition)

• Crank Hub Failure
  • Description/Symptoms: The S58 engine has been known to have potential issues with the crank hub, specifically the friction plates slipping on the crank hub. This slippage causes timing issues which in turn can cause the engine to severely damage itself. Symptoms include a check engine light, misfires, and reduced power. This issue is more prevalent in tuned vehicles.
  • Solution: Replacing the factory crank hub with a stronger, aftermarket single-piece crank hub. Some people will pin the factory crank hub which should offer similar results.
  • Estimated Cost to Fix: $2,500 - $5,000+
  • Recalls: None Found

Transmission

6-Speed Manual (Base Model)

• Difficulty Shifting into Gear
  • Description/Symptoms: Some owners have reported difficulty shifting into certain gears, particularly when the transmission is cold. This can manifest as a notchy or grinding feeling.
  • Solution: In some cases, replacing the transmission fluid with a higher quality fluid can improve shift quality. In other cases, the synchros may be worn or defective and require replacement.
  • Estimated Cost to Fix: $50 - $5000+ (depending on severity, fluid change vs transmission rebuild)
  • Recalls: None Found

8-Speed Automatic (Competition Model)

• Rough Shifting/Hesitation
  • Description/Symptoms: Some owners have reported experiencing rough or jerky shifts, especially at lower speeds. Hesitation during acceleration has also been noted.
  • Solution: A software update or transmission recalibration may resolve the issue. In more severe cases, replacement of valve body components within the transmission may be necessary.
  • Estimated Cost to Fix: $150 - $3,000+
  • Recalls: None Found

Suspension

• Adaptive Damper Malfunction
  • Description/Symptoms: The adaptive suspension system (if equipped) can sometimes exhibit malfunctions, leading to error messages or inconsistent damping characteristics. This may result in a harsher or bouncier ride.
  • Solution: Diagnosis and replacement of the faulty damper(s) or associated sensors.
  • Estimated Cost to Fix: $1,000 - $3,000+ (depending on the affected damper and labor)
  • Recalls: None Found

Electrical

• Infotainment System Freezing/Crashing
  • Description/Symptoms: The iDrive infotainment system can occasionally freeze, crash, or exhibit lag. This may require a system reboot.
  • Solution: A software update may resolve the issue. In more severe cases, the iDrive head unit may need to be replaced.
  • Estimated Cost to Fix: $0 - $2,000+ (Software update is usually free, iDrive unit replacement can be expensive)
  • Recalls: None Found
• Sensor Issues
  • Description/Symptoms: A common issue among owners is issues with the driver assistance features such as lane keep assist, lane departure warnings, and the adaptive cruise control system being unreliable. The issues generally start with errors displaying on the dash and the systems no longer working.
  • Solution: Replacing the faulty sensors and/or control units for the driver assist features.
  • Estimated Cost to Fix: $500 - $2,000+
  • Recalls: None Found

Exterior

• No Issues Found

Interior

• Rattling/Squeaking Noises
  • Description/Symptoms: Some owners have reported experiencing rattling or squeaking noises emanating from the dashboard, door panels, or rear shelf.
  • Solution: Locating and addressing the source of the noise, which may involve tightening fasteners, adding sound deadening material, or replacing trim pieces.
  • Estimated Cost to Fix: $50 - $500+ (depending on the complexity of the repair)
  • Recalls: None Found

Summary

The 2021 BMW M3, while offering exceptional performance, has several reported issues. The most concerning is the potential crank hub failure of the S58 engine, which can be catastrophic and costly to repair, especially on tuned vehicles. Other issues include potential rough transmission shifting, adaptive damper malfunctions, and infotainment system glitches. Interior rattles and squeaks are also common. The severity and cost of these issues vary, but potential buyers should be aware of these potential problems.