2009 Mercedes-Benz MBO 12000

The 2009 Mercedes-Benz ML350 is a luxury mid-size SUV that offers a blend of comfort, performance, and style. The base engine is a 3.5L V6 producing 268 horsepower and 258 lb-ft of torque. Other engine options include a 5.5L V8 (ML550), a 3.0L Turbo Diesel V6 (ML320 BlueTEC), and a high-performance 6.2L V8 (ML63 AMG). All engines are paired with a 7-speed automatic transmission. Owners often praise the ML350 for its smooth ride, luxurious interior, and powerful engine options. Common complaints include electronic issues, higher maintenance costs, and occasional suspension problems.

Engine

3.5L V6 (M272)

• Balance Shaft Failure
  • Description/Symptoms: Ticking or rattling noise, especially at idle. Rough engine running, check engine light illuminated.
  • Solution: Replacement of the balance shaft and related components.
  • Estimated Cost to Fix: $2,500 - $5,000+
  • Recalls: None Found
• Camshaft Adjuster (Magnet) Failure
  • Description/Symptoms: Check engine light illuminated, rough idle, reduced power.
  • Solution: Replacement of the faulty camshaft adjuster magnet(s).
  • Estimated Cost to Fix: $300 - $800
  • Recalls: None Found

3.0L Turbo Diesel V6 (OM642)

• Oil Cooler Seal Leaks
  • Description/Symptoms: Oil leaks visible on the engine, especially near the oil cooler. Oil consumption may increase.
  • Solution: Replacement of the oil cooler seals. Can also replace the oil cooler as well if it is damaged.
  • Estimated Cost to Fix: $1,200 - $2,000
  • Recalls: None Found
• Swirl Motor Failure
  • Description/Symptoms: Check engine light illuminated, reduced power, possible limp mode.
  • Solution: Replacement of the swirl motor.
  • Estimated Cost to Fix: $800 - $1,500
  • Recalls: None Found

5.5L V8 (M273)

• Camshaft Adjuster (Magnet) Failure
  • Description/Symptoms: Check engine light illuminated, rough idle, reduced power.
  • Solution: Replacement of the faulty camshaft adjuster magnet(s).
  • Estimated Cost to Fix: $300 - $800
  • Recalls: None Found

6.2L V8 (M156)

• Head Bolt Failure
  • Description/Symptoms: Coolant loss, overheating, milky oil, and possible engine damage.
  • Solution: Replacement of the head bolts (updated version is recommended) and potentially head gaskets.
  • Estimated Cost to Fix: $5,000 - $10,000+
  • Recalls: None Found

Transmission

7-Speed Automatic (722.9)

• Valve Body Issues
  • Description/Symptoms: Harsh shifting, delayed engagement, slipping between gears, getting stuck in gear, or a complete loss of drive.
  • Solution: Replacement or rebuild of the valve body. In some cases, the entire transmission may need to be replaced.
  • Estimated Cost to Fix: $1,500 - $4,000+
  • Recalls: None Found
• Conductor Plate Failure
  • Description/Symptoms: Erratic shifting, limp mode, check engine light illuminated.
  • Solution: Replacement of the conductor plate.
  • Estimated Cost to Fix: $800 - $1,500
  • Recalls: None Found

Suspension

• Airmatic Suspension Failure (if equipped)
  • Description/Symptoms: Vehicle sagging, uneven ride height, air compressor running constantly, suspension warning lights.
  • Solution: Replacement of leaking air struts/springs, air compressor, or valve block.
  • Estimated Cost to Fix: $1,000 - $3,000+ per component
  • Recalls: None Found
• Lower Control Arm Bushing Failure
  • Description/Symptoms: Squeaking or creaking noises coming from the front suspension, especially when going over bumps or turning. Loose or vague steering feel. Uneven tire wear.
  • Solution: Replacement of the lower control arm bushings.
  • Estimated Cost to Fix: $500 - $1,000+
  • Recalls: None Found

Electrical

• EIS (Electronic Ignition Switch) Failure
  • Description/Symptoms: Key not recognized, inability to start the vehicle.
  • Solution: Replacement of the EIS module, which often requires programming.
  • Estimated Cost to Fix: $800 - $2,000+
  • Recalls: None Found
• SAM (Signal Acquisition Module) Issues
  • Description/Symptoms: Various electrical malfunctions, such as lights not working, wipers malfunctioning, or other electronic components failing.
  • Solution: Replacement or reprogramming of the affected SAM module.
  • Estimated Cost to Fix: $500 - $1,500+
  • Recalls: None Found

Exterior

• Sunroof Issues
  • Description/Symptoms: Sunroof not opening or closing properly, motor failure, or water leaks.
  • Solution: Repair or replacement of the sunroof motor, tracks, or seals.
  • Estimated Cost to Fix: $300 - $1,000+
  • Recalls: None Found

Interior

• Navigation/Entertainment System Malfunctions
  • Description/Symptoms: System freezing, display issues, failure to recognize CDs or DVDs.
  • Solution: Software update or replacement of the head unit.
  • Estimated Cost to Fix: $300 - $1,500+
  • Recalls: None Found

Summary The 2009 Mercedes-Benz ML350, while a luxurious and capable SUV, is prone to certain issues. Engine problems, particularly the balance shaft issue in the 3.5L V6 and head bolt issues in the 6.2L V8, can be very costly to repair. The 7-speed automatic transmission is also a potential source of trouble. Suspension and electrical problems add to the overall cost of ownership. Potential buyers should be aware of these common issues and factor in potential repair costs when considering a purchase. While some problems are relatively minor, others can lead to significant expenses.