2012 Mercedes-Benz ML350

The 2012 Mercedes-Benz ML350 is a luxury SUV that offers a comfortable ride and a refined interior. The ML350 comes standard with a 3.5-liter V6 engine producing 302 horsepower and 273 lb-ft of torque, paired with a 7-speed automatic transmission. Other engine options available in 2012 included a diesel engine and a more powerful V8 engine in the ML550. Owners appreciate the ML350’s luxurious features, smooth handling, and spacious cabin. Common complaints include expensive maintenance, some reliability issues, and the complicated COMAND infotainment system.

Engine

3.5L V6 Engine

• Engine Oil Leaks
  • Description/Symptoms: Oil leaks can develop from various locations, including the valve cover gaskets, oil filter housing, and the front crankshaft seal. Symptoms include visible oil leaks, a burning oil smell, and low oil levels.
  • Solution: Replacing the leaking gaskets or seals.
  • Estimated Cost to Fix: $200 - $1000+ depending on the location and complexity of the repair.
  • Recalls: None Found
• Camshaft Adjuster (Magnet) Plugs Leaking
  • Description/Symptoms: These plugs on the front of the engine can leak, causing oil to drip onto the exhaust manifold. This results in a burning oil smell.
  • Solution: Replacing the camshaft adjuster plugs.
  • Estimated Cost to Fix: $100 - $300
  • Recalls: None Found
• Check Engine Light Due to Camshaft Position Sensor
  • Description/Symptoms: The check engine light turns on and diagnostic codes indicate a problem with the camshaft position sensor. Symptoms include poor engine performance, rough idling, or stalling.
  • Solution: Replacing the faulty camshaft position sensor(s).
  • Estimated Cost to Fix: $150 - $400
  • Recalls: None Found

Transmission

7-Speed Automatic (7G-TRONIC)

• Rough or Delayed Shifting
  • Description/Symptoms: Some owners have reported experiencing rough or delayed shifts, particularly between certain gears. This can sometimes be accompanied by a “clunking” noise.
  • Solution: A software update may resolve minor issues. More severe cases could require valve body replacement or transmission rebuild/replacement.
  • Estimated Cost to Fix: $200 (software update) - $5,000+ (transmission rebuild/replacement)
  • Recalls: None Found
• Torque Converter Issues
  • Description/Symptoms: Torque converter shudder or vibration, especially at low speeds.
  • Solution: Torque converter replacement.
  • Estimated Cost to Fix: $1,500 - $3,000
  • Recalls: None Found

Suspension

• Air Suspension Problems (If Equipped)
  • Description/Symptoms: Sagging suspension, particularly overnight. Compressor failure, leading to inability to raise or lower the vehicle. Error messages related to the air suspension system.
  • Solution: Replacing faulty air struts, compressor, or air lines.
  • Estimated Cost to Fix: $800 - $2,000+ per strut, $500 - $1,500 for the compressor.
  • Recalls: None Found
• Airmatic Compressor Relay Failure
  • Description/Symptoms: Compressor running continuously, draining the battery, or compressor not running at all.
  • Solution: Replacing the Airmatic compressor relay.
  • Estimated Cost to Fix: $50 - $200
  • Recalls: None Found

Electrical

• Battery Drain Issues
  • Description/Symptoms: The battery drains overnight or after a short period of inactivity.
  • Solution: Identifying and resolving parasitic draws, which could be caused by faulty modules, lights, or other electrical components.
  • Estimated Cost to Fix: $100 - $500+ depending on the source of the drain.
  • Recalls: None Found
• COMAND System Malfunctions
  • Description/Symptoms: The COMAND infotainment system can experience various issues, including freezing, crashing, display problems, or inability to control certain functions.
  • Solution: Software updates may resolve some issues. In severe cases, the COMAND unit may need to be replaced.
  • Estimated Cost to Fix: $100 (Software Update) - $1,500+ (Replacement)
  • Recalls: None Found
• SAM (Signal Acquisition Module) Failure
  • Description/Symptoms: The SAM controls various electrical functions. Failure can lead to issues with lights, wipers, locks, and other systems.
  • Solution: Replacing the faulty SAM unit.
  • Estimated Cost to Fix: $500 - $1,500
  • Recalls: None Found

Exterior

• Sunroof Issues
  • Description/Symptoms: Sunroof can be difficult to open or close, makes grinding noises, or gets stuck.
  • Solution: Cleaning and lubricating the sunroof tracks and mechanism. Replacing the sunroof motor or the entire sunroof assembly in more severe cases.
  • Estimated Cost to Fix: $50 - $100 (Lubrication) - $1,000+ (Replacement)
  • Recalls: None Found

Interior

• Power Seat Malfunctions
  • Description/Symptoms: Power seats not adjusting properly or making clicking noises.
  • Solution: Replacing the seat motor or repairing wiring issues.
  • Estimated Cost to Fix: $200 - $800
  • Recalls: None Found

Summary

The 2012 Mercedes-Benz ML350 can be a rewarding vehicle to own, but potential buyers should be aware of the common issues mentioned. Engine oil leaks, transmission issues, and air suspension problems can be costly to repair. Electrical glitches, particularly with the COMAND system, can also be frustrating. While some issues are relatively minor, others can be quite expensive to fix, so a thorough inspection and pre-purchase inspection are recommended. The severity of these issues varies greatly, but potential repair costs can range from a few hundred dollars to several thousand dollars.