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2005 Mercedes-Benz ML500

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By Research the Car 4 min read

The 2005 Mercedes-Benz ML500 is a mid-size luxury SUV that offers a blend of comfort, capability, and style. Besides the ML500, the model year also includes the ML350 with a 3.7L V6 and the ML320 CDI with a 3.0L Diesel engine. The ML500 is equipped with a 5.0L V8 engine producing 302 horsepower and 339 lb-ft of torque, paired with a 722.9 7-speed automatic transmission. Owners often appreciate the vehicle’s smooth ride, powerful engine (in the ML500), and luxurious interior. Some common complaints revolve around maintenance costs, electrical issues, and certain aspects of reliability.

Engine

5.0L V8

  • Oil Leaks
    • Description/Symptoms: Oil leaks can occur from various points in the engine, including valve cover gaskets, oil pan gasket, rear main seal, and timing cover. Symptoms include visible oil leaks, oil consumption, and a burning oil smell.
    • Solution: Replacing the leaking gasket or seal. Thorough cleaning of the affected area is essential.
    • Estimated Cost to Fix: $150 - $1000+ depending on the location and complexity of the leak.
    • Recalls: None Found
  • Camshaft Adjuster Plugs
    • Description/Symptoms: The camshaft adjuster plugs (located at the rear of the cylinder heads) can leak oil.
    • Solution: Replace the camshaft adjuster plugs.
    • Estimated Cost to Fix: $100 - $300
    • Recalls: None Found

Transmission

722.9 7-Speed Automatic

  • Valve Body Issues
    • Description/Symptoms: The 722.9 transmission is known for valve body problems. Symptoms include harsh or erratic shifting, delayed engagement, and transmission slipping.
    • Solution: Replacing or rebuilding the valve body. Sometimes, a software update can mitigate the issue.
    • Estimated Cost to Fix: $800 - $2000+
    • Recalls: None Found
  • Conductor Plate Failure
    • Description/Symptoms: The conductor plate, located inside the transmission, houses the speed sensors and other electronic components. Failure can cause shifting problems, limp mode, and diagnostic trouble codes.
    • Solution: Replacing the conductor plate and potentially the valve body.
    • Estimated Cost to Fix: $600 - $1500
    • Recalls: None Found

Suspension

  • Airmatic Suspension Failure
    • Description/Symptoms: The Airmatic air suspension system, if equipped, is prone to leaks and compressor failures. Symptoms include a sagging vehicle, particularly overnight, a “Suspension Malfunction” warning, and a noisy or non-functional air compressor.
    • Solution: Replacing leaking air struts, repairing or replacing the air compressor, and checking for leaks in the air lines.
    • Estimated Cost to Fix: $500 - $2000+ per strut, $400 - $800 for the compressor.
    • Recalls: None Found
  • Ball Joint Failure
    • Description/Symptoms: Worn ball joints can cause clunking noises in the front suspension, and loose or unstable steering.
    • Solution: Replacement of worn ball joints. Replacing control arms as an assembly is also an option depending on the location of the ball joint.
    • Estimated Cost to Fix: $200 - $800+ per side depending on the extent of the repair.
    • Recalls: None Found

Electrical

  • EIS (Electronic Ignition Switch) Failure
    • Description/Symptoms: The EIS can fail, preventing the key from turning or the car from starting. This is a common issue in this era of Mercedes vehicles.
    • Solution: Replacing the EIS and programming it to the vehicle.
    • Estimated Cost to Fix: $800 - $1500
    • Recalls: None Found
  • SAM (Signal Acquisition Module) Failure
    • Description/Symptoms: The SAM controls various electrical functions. Failures can cause issues with lights, wipers, power windows, and other electrical components.
    • Solution: Replacing the faulty SAM unit and programming it to the vehicle.
    • Estimated Cost to Fix: $500 - $1200
    • Recalls: None Found
  • Battery Drain Issues
    • Description/Symptoms: Parasitic draw can lead to a dead battery, especially if the vehicle sits for extended periods. This can be due to a faulty component not shutting down properly.
    • Solution: Identifying the source of the parasitic draw and repairing or replacing the faulty component.
    • Estimated Cost to Fix: $100 - $500+ depending on the complexity of the issue.
    • Recalls: None Found

Exterior

  • Rust
    • Description/Symptoms: Rust can develop on the body, especially in areas prone to salt exposure.
    • Solution: Repair or replacement of rusted body panels.
    • Estimated Cost to Fix: $200 - $2000+, depending on the extent of the rust.
    • Recalls: None Found

Interior

  • Sunroof Issues
    • Description/Symptoms: The sunroof mechanism can fail, causing it to jam, leak, or not open/close properly.
    • Solution: Repair or replacement of the sunroof motor, tracks, or seals.
    • Estimated Cost to Fix: $300 - $1000
    • Recalls: None Found
  • Navigation System Failure
    • Description/Symptoms: The factory navigation system (if equipped) can fail or become outdated.
    • Solution: Replacement of the head unit or navigation components.
    • Estimated Cost to Fix: $300 - $1000+ for aftermarket options, potentially more for OEM repairs.
    • Recalls: None Found

Summary The 2005 Mercedes-Benz ML500, while a comfortable and powerful SUV, is prone to several common issues as it ages. These include oil leaks and potential valve body issues in the transmission, Airmatic suspension problems, electrical glitches (EIS, SAM), and interior issues. The severity and cost of these issues vary, but many of them can be expensive to repair due to the complexity of the vehicle and the cost of Mercedes-Benz parts. Potential buyers should be aware of these potential problems and factor in maintenance costs when considering purchasing this model.

Mercedes-Benz, ML500
Mercedes-Benz ML500 2005
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