2015 Mercedes-Benz ML550

The 2015 Mercedes-Benz ML550 is a luxury SUV that offers a blend of performance and comfort. This model year came standard with a 4.7-liter twin-turbo V8 engine, producing 429 horsepower and 516 lb-ft of torque. Other engine options included a 3.5-liter V6 (ML350), a diesel 3.0-liter V6 (ML250 BlueTEC and ML350 BlueTEC), and a more powerful 5.5-liter V8 (ML63 AMG). All engine options came exclusively with the 7G-TRONIC PLUS 7-speed automatic transmission. Owners generally appreciate the ML550’s powerful engine, luxurious interior, and comfortable ride. Common complaints often revolve around higher maintenance costs and occasional electrical issues.

Engine

4.7L Twin-Turbo V8 (M278)

• Oil Leaks
  • Description/Symptoms: Oil leaks can occur from various locations, including valve cover gaskets, timing chain cover, and oil filter housing. Symptoms include visible oil leaks under the vehicle, a burning oil smell, and low oil levels.
  • Solution: Replacing the leaking gaskets or seals.
  • Estimated Cost to Fix: $200 - $1,500+ depending on the location and severity of the leak.
• Turbocharger Issues
  • Description/Symptoms: The turbochargers can experience failures due to oil starvation or general wear. Symptoms include reduced power, whistling noises from the engine bay, and potentially fault codes related to turbocharger performance.
  • Solution: Replacing or rebuilding the turbocharger(s).
  • Estimated Cost to Fix: $2,500 - $5,000+ per turbocharger depending on whether it is replaced or rebuilt.
• Fuel Injector Problems
  • Description/Symptoms: Fuel injectors can become clogged or fail, leading to poor engine performance, rough idling, misfires, and potentially engine stalling.
  • Solution: Replacing the faulty fuel injector(s).
  • Estimated Cost to Fix: $200 - $500+ per injector.

Transmission

7G-TRONIC PLUS (722.9)

• Valve Body Issues
  • Description/Symptoms: The valve body within the 7G-TRONIC transmission can experience wear and tear, leading to harsh shifting, delayed engagement, and slipping between gears.
  • Solution: Replacing or rebuilding the valve body.
  • Estimated Cost to Fix: $1,200 - $2,500+
  • Recalls: None Found
• Torque Converter Failure
  • Description/Symptoms: Torque converter issues can manifest as shuddering during acceleration, vibrations, and potentially transmission failure.
  • Solution: Replacing the torque converter.
  • Estimated Cost to Fix: $1,500 - $3,000+

Suspension

• Air Suspension Problems (Airmatic)
  • Description/Symptoms: The Airmatic air suspension system can experience failures in the air struts, air compressor, or valve block. Symptoms include the vehicle sitting unevenly, a sagging suspension, and error messages related to the suspension system.
  • Solution: Replacing the faulty air struts, compressor, or valve block.
  • Estimated Cost to Fix: $800 - $2,000+ per strut; $500 - $1,500+ for the compressor; $300 - $800+ for the valve block.

Electrical

• Battery Drain
  • Description/Symptoms: Excessive battery drain can occur due to various electrical components not shutting off properly, leading to a dead battery.
  • Solution: Diagnosing and repairing the parasitic draw.
  • Estimated Cost to Fix: $150 - $500+ depending on the source of the drain.
  • Recalls: None Found
• COMAND System Issues
  • Description/Symptoms: The COMAND infotainment system can experience glitches, freezing, and display issues.
  • Solution: Updating the software or replacing the COMAND unit.
  • Estimated Cost to Fix: $100 - $1,500+ depending on the issue and solution.
  • Recalls: None Found

Exterior

• Sunroof Problems
  • Description/Symptoms: The sunroof mechanism can fail, leading to difficulty opening or closing the sunroof, or water leaks.
  • Solution: Repairing or replacing the sunroof mechanism.
  • Estimated Cost to Fix: $300 - $1,000+

Interior

• Seat Motor Failure
  • Description/Symptoms: The electric seat motors can fail, leading to difficulty adjusting the seat position.
  • Solution: Replacing the faulty seat motor.
  • Estimated Cost to Fix: $200 - $600+ per motor.
  • Recalls: None Found

Summary

The 2015 Mercedes-Benz ML550, while luxurious and powerful, can present owners with a range of issues. Engine oil leaks and turbocharger problems on the M278 engine can be costly to repair. The 7G-TRONIC transmission can also develop valve body and torque converter issues. The Airmatic suspension is also a known potential failure point. Electrical issues, such as battery drain and COMAND system malfunctions, can also arise. The severity of these issues ranges from minor inconveniences to major repairs, with costs varying widely depending on the specific problem and the chosen repair method. Prospective buyers should be aware of these potential problems and factor them into their ownership costs.