2009 Mercedes-Benz ML350

The 2009 Mercedes-Benz ML350 is a mid-size luxury SUV known for its comfort, build quality, and available features. The ML350 came standard with a 3.5L V6 engine producing 268 horsepower and 258 lb-ft of torque, paired with a 7-speed automatic transmission (7G-Tronic). Other engine options included a diesel V6 and a more powerful V8. Owners generally appreciate the vehicle’s smooth ride, luxurious interior, and confident handling, but common complaints include electrical issues, high maintenance costs, and occasional drivetrain problems.

Engine

3.5L V6 Engine

• Balance Shaft Sprocket Wear
  • Description/Symptoms: A worn balance shaft sprocket can cause a rough idle, engine noise (rattling or ticking), check engine light, and potential engine damage if left unaddressed.
  • Solution: Replacement of the balance shaft and sprocket is required. This is a labor-intensive job.
  • Estimated Cost to Fix: $2,000 - $4,000+
  • Recalls: None Found
• Camshaft Adjuster Solenoid Failure
  • Description/Symptoms: The camshaft adjuster solenoid can fail, causing a check engine light, rough idle, poor performance, and potential stalling.
  • Solution: Replacement of the faulty camshaft adjuster solenoid.
  • Estimated Cost to Fix: $200 - $500
  • Recalls: None Found
• Oil Leaks (Valve Cover Gaskets, Oil Filter Housing)
  • Description/Symptoms: Oil leaks are common from the valve cover gaskets and oil filter housing. Symptoms include visible oil leaks, burning oil smell, and low oil level.
  • Solution: Replacement of the valve cover gaskets and/or oil filter housing gasket.
  • Estimated Cost to Fix: $200 - $800 (depending on the location of the leak)
  • Recalls: None Found

Transmission

7G-Tronic (722.9) 7-Speed Automatic Transmission

• Valve Body Issues
  • Description/Symptoms: The valve body, specifically the conductor plate within, can fail, causing harsh shifting, erratic gear changes, and getting stuck in a gear.
  • Solution: Replacement of the valve body/conductor plate.
  • Estimated Cost to Fix: $1,000 - $2,000+
  • Recalls: None Found
• Torque Converter Failure
  • Description/Symptoms: Torque converter issues can cause shuddering during acceleration, especially at lower speeds, and can lead to transmission failure if not addressed.
  • Solution: Replacement of the torque converter.
  • Estimated Cost to Fix: $1,500 - $3,000+
  • Recalls: None Found

Suspension

• Air Suspension Failure (Airmatic)
  • Description/Symptoms: If equipped with Airmatic suspension, owners may experience issues with the air struts leaking, the compressor failing, or the system malfunctioning, resulting in the vehicle sitting unevenly or not raising/lowering properly.
  • Solution: Replacement of the faulty air struts, compressor, or other components of the Airmatic system.
  • Estimated Cost to Fix: $800 - $2,000+ (per strut, plus compressor cost)
  • Recalls: None Found
• Lower Control Arm Bushings
  • Description/Symptoms: Worn lower control arm bushings cause clunking noises, imprecise steering, and uneven tire wear.
  • Solution: Replacement of the lower control arm bushings.
  • Estimated Cost to Fix: $300 - $800
  • Recalls: None Found

Electrical

• EIS (Electronic Ignition Switch) Failure
  • Description/Symptoms: The EIS can fail, preventing the vehicle from starting.
  • Solution: Replacement of the EIS unit and reprogramming.
  • Estimated Cost to Fix: $800 - $1,500+
  • Recalls: None Found
• SAM (Signal Acquisition Module) Failure
  • Description/Symptoms: SAM units control various electrical functions. Failure can lead to issues with lights, wipers, power windows, and other electrical components.
  • Solution: Replacement of the faulty SAM unit and reprogramming.
  • Estimated Cost to Fix: $500 - $1,200+
  • Recalls: None Found
• Power Window Regulator Failure
  • Description/Symptoms: Power windows may stop working or operate erratically due to regulator failure.
  • Solution: Replacement of the faulty power window regulator.
  • Estimated Cost to Fix: $200 - $500
  • Recalls: None Found

Exterior

• Rust
  • Description/Symptoms: Rust can form on the undercarriage, wheel arches, and other areas, especially in regions with harsh winters or salt exposure.
  • Solution: Rust repair, which may involve sanding, welding, and repainting. Prevention with undercoating is recommended.
  • Estimated Cost to Fix: $200 - $2,000+ (depending on severity)
  • Recalls: None Found

Interior

• Sunroof Issues
  • Description/Symptoms: Sunroofs can experience issues with the motor, tracks, or seals, leading to difficulty opening/closing or leaks.
  • Solution: Repair or replacement of the sunroof motor, tracks, or seals.
  • Estimated Cost to Fix: $200 - $1,000+
  • Recalls: None Found

Summary

The 2009 Mercedes-Benz ML350 can be a comfortable and luxurious SUV, but it is important to be aware of the potential issues. The most significant and costly problems often relate to the engine (balance shaft), transmission (valve body), and air suspension (if equipped). Electrical issues (EIS, SAM) are also relatively common. Due to the age of the vehicle, maintenance is crucial, and preventative repairs can save money in the long run. Repair costs can be high due to the cost of Mercedes-Benz parts and specialized labor requirements. Prospective buyers should have a thorough pre-purchase inspection performed by a qualified mechanic experienced with Mercedes-Benz vehicles.