2009 Mercedes-Benz S450

The 2009 Mercedes-Benz S450 is a luxury sedan known for its comfortable ride, opulent interior, and advanced technology for its time. The S450 variant comes with a 4.7L V8 engine producing 335 horsepower and 339 lb-ft of torque. Other engine options available for the 2009 S-Class include the S550 which had a 5.5L V8 and the S600 which has a 5.5L V12. All engines are paired with a 7-speed automatic transmission. Owners often praise the S450 for its smooth power delivery, quiet cabin, and overall refinement. Common complaints often revolve around the high cost of maintenance and repairs, as well as the complexity of the vehicle’s electronics, which can sometimes lead to issues.

Engine

4.7L V8

• Oil Leaks
  • Description/Symptoms: Oil leaks can occur from various locations, including the valve cover gaskets, oil filter housing, and rear main seal. Symptoms include visible oil drips under the car, a burning oil smell, and low oil levels.
  • Solution: Replacing the leaking gaskets or seals. For more significant leaks, the oil filter housing or rear main seal may need replacement.
  • Estimated Cost to Fix: $200 - $1500+ depending on the location and severity of the leak.
  • Recalls: None Found
• Camshaft Adjuster Solenoid Failure
  • Description/Symptoms: The camshaft adjuster solenoids can fail, leading to rough idling, poor engine performance, and a check engine light.
  • Solution: Replacing the faulty camshaft adjuster solenoid.
  • Estimated Cost to Fix: $200 - $500
  • Recalls: None Found

Transmission

7-Speed Automatic (7G-Tronic)

• Rough Shifting
  • Description/Symptoms: The 7G-Tronic transmission can sometimes exhibit rough or delayed shifting, particularly between lower gears. This can be caused by valve body issues or low transmission fluid.
  • Solution: Performing a transmission fluid flush and filter change. If the problem persists, the valve body may need to be rebuilt or replaced.
  • Estimated Cost to Fix: $300 - $3,000+ (valve body replacement)
  • Recalls: None Found
• Torque Converter Failure
  • Description/Symptoms: Torque converter failure can result in shuddering at low speeds, poor acceleration, and transmission slippage.
  • Solution: Replacing the torque converter.
  • Estimated Cost to Fix: $1,500 - $3,000
  • Recalls: None Found

Suspension

• Airmatic Suspension Issues
  • Description/Symptoms: The Airmatic air suspension system is prone to leaks and failures. Symptoms include the car sitting unevenly, the suspension compressor running constantly, and error messages on the dashboard.
  • Solution: Replacing the leaking air struts, the air compressor, or the valve block.
  • Estimated Cost to Fix: $800 - $2,000+ per strut, $500 - $1,500 for the compressor.
  • Recalls: None Found

Electrical

• Battery Drain
  • Description/Symptoms: Many owners report issues with excessive battery drain, which can be caused by a variety of factors, including faulty modules, aftermarket accessories, or a failing alternator.
  • Solution: Diagnosing the source of the drain and replacing the faulty component. This may involve testing various modules and wiring harnesses.
  • Estimated Cost to Fix: $100 - $1,000+ depending on the cause.
  • Recalls: None Found
• COMAND System Malfunctions
  • Description/Symptoms: The COMAND infotainment system can experience a range of issues, including freezing, crashing, and navigation problems.
  • Solution: Sometimes a software update can resolve the issue. In other cases, the COMAND unit may need to be replaced.
  • Estimated Cost to Fix: $100 - $2,000+ (replacement)
  • Recalls: None Found

Exterior

• Adaptive Headlight Malfunctions
  • Description/Symptoms: The adaptive headlights can experience malfunctions, causing them to aim incorrectly or fail to function altogether.
  • Solution: Replacing the headlight control module or the headlight assembly.
  • Estimated Cost to Fix: $500 - $1,500+
  • Recalls: None Found

Interior

• Sunroof Issues
  • Description/Symptoms: Sunroofs can sometimes develop issues with the motor, tracks, or seals, causing them to become stuck, leak, or make excessive noise.
  • Solution: Repairing or replacing the sunroof motor, tracks, or seals.
  • Estimated Cost to Fix: $300 - $1,000+
  • Recalls: None Found
• Door Lock Actuator Failure
  • Description/Symptoms: Door lock actuators can fail, preventing the doors from locking or unlocking properly.
  • Solution: Replacing the faulty door lock actuator.
  • Estimated Cost to Fix: $200 - $500 per door.
  • Recalls: None Found

Summary

The 2009 Mercedes-Benz S450 offers a luxurious and comfortable driving experience, but it is not without its potential issues. The most common problems reported by owners relate to the Airmatic suspension, electrical system, and transmission. Repairs can be costly, particularly for the suspension and complex electrical components. While engine issues such as oil leaks can occur, they are not as pervasive as the aforementioned problems. Potential buyers should be aware of these common issues and factor in the potential cost of repairs when considering a purchase.