2021 Mercedes-Benz GLC300

The 2021 Mercedes-Benz GLC300 is a popular luxury compact SUV known for its comfortable ride, upscale interior, and elegant styling. The GLC300 is powered by a 2.0-liter turbocharged inline-4 engine producing 255 horsepower and 273 lb-ft of torque, paired with a 9G-TRONIC 9-speed automatic transmission. While the GLC300 offers a refined driving experience, some owners have reported certain issues. Some owners praise the vehicle’s comfortable seats, quiet cabin, and user-friendly infotainment system, while others dislike the somewhat firm ride and the cost of maintenance.

Engine

2.0L Turbocharged Inline-4 (M264)

• Engine Misfires
  • Description/Symptoms: Engine misfires, rough idling, check engine light illuminated. Can be caused by faulty spark plugs, ignition coils, or fuel injectors.
  • Solution: Diagnosis to determine the cause of the misfire. Replace faulty spark plugs, ignition coils, or fuel injectors as needed.
  • Estimated Cost to Fix: $150 - $600+
  • Recalls: None Found
• Oil Leaks
  • Description/Symptoms: Oil spots under the vehicle, burning oil smell, low oil level. Potential leaks from the valve cover gasket, oil filter housing, or rear main seal.
  • Solution: Identify the source of the leak. Replace the leaking gasket or seal.
  • Estimated Cost to Fix: $200 - $1000+
  • Recalls: None Found
• Turbocharger Issues
  • Description/Symptoms: Loss of power, whistling sound from the engine, check engine light. Potential issues with the turbocharger wastegate or bearing failure.
  • Solution: Diagnose the turbocharger. Replace the turbocharger if necessary.
  • Estimated Cost to Fix: $1500 - $3000+
  • Recalls: None Found

Transmission

9G-TRONIC 9-Speed Automatic (725.0)

• Rough Shifting
  • Description/Symptoms: Harsh or delayed shifts, particularly between certain gears (e.g., 2nd to 3rd).
  • Solution: Check the transmission fluid level and condition. Perform a transmission fluid flush. In some cases, a software update or valve body replacement may be necessary.
  • Estimated Cost to Fix: $300 - $2500+
  • Recalls: None Found
• Hesitation or Slipping
  • Description/Symptoms: Delay in acceleration, engine revving without corresponding speed increase.
  • Solution: Inspect the transmission for leaks and check the fluid level and condition. A more in-depth diagnosis may be required to determine if the torque converter or internal components are failing.
  • Estimated Cost to Fix: $400 - $4000+
  • Recalls: None Found

Suspension

• Air Suspension Issues (if equipped)
  • Description/Symptoms: Vehicle sagging on one side, compressor failing to inflate the suspension, error message on the dashboard. Potential issues with the air struts, compressor, or air lines.
  • Solution: Diagnose the air suspension system. Replace faulty components as needed.
  • Estimated Cost to Fix: $800 - $3000+
  • Recalls: None Found

Electrical

• Infotainment System Freezing or Crashing
  • Description/Symptoms: The MBUX system freezes, becomes unresponsive, or restarts unexpectedly.
  • Solution: Perform a system reset. Software updates may be available to address these issues. In some cases, the head unit may need to be replaced.
  • Estimated Cost to Fix: $0 (Software Update) - $1500+
  • Recalls: None Found
• Sensor Malfunctions
  • Description/Symptoms: Issues with parking sensors, blind spot monitoring, or other driver-assistance features.
  • Solution: Diagnose the faulty sensor and replace it.
  • Estimated Cost to Fix: $200 - $800+
  • Recalls: None Found
• Battery Drain
  • Description/Symptoms: Vehicle battery drains quickly, especially when parked for extended periods. Can be caused by a parasitic draw from an electrical component.
  • Solution: Identify the source of the parasitic draw. Repair or replace the faulty component.
  • Estimated Cost to Fix: $100 - $500+
  • Recalls: None Found

Exterior

• Sunroof Issues
  • Description/Symptoms: Sunroof may not open or close properly, or may make excessive noise.
  • Solution: Inspect the sunroof mechanism for obstructions or damage. Lubricate the tracks and moving parts. In some cases, the sunroof motor or regulator may need to be replaced.
  • Estimated Cost to Fix: $200 - $1000+
  • Recalls: None Found

Interior

• MBUX System Glitches
  • Description/Symptoms: Touchscreen unresponsiveness, voice command recognition errors, and inconsistent navigation.
  • Solution: Software updates are the most common solution. In rare cases, hardware replacement might be necessary.
  • Estimated Cost to Fix: $0 (Software Update) - $1500+
  • Recalls: None Found
• Seat Motor Failure
  • Description/Symptoms: Difficulty adjusting seat position, clicking noises from the seat motor.
  • Solution: Replace the faulty seat motor or related components.
  • Estimated Cost to Fix: $300 - $1000+
  • Recalls: None Found

Summary

The 2021 Mercedes-Benz GLC300, while generally reliable, can experience issues ranging from minor electrical glitches to more significant engine and transmission problems. Electrical issues such as MBUX glitches are more common and typically less expensive to resolve. Engine issues such as oil leaks and transmission issues such as rough shifting can be more severe and costly to fix. Potential buyers should be aware of these potential issues and have the vehicle inspected by a qualified mechanic before purchasing.