2009 Mercedes-Benz SLK350

The 2009 Mercedes-Benz SLK350 is a stylish and sporty roadster, known for its retractable hardtop, providing both open-air enjoyment and coupe-like comfort. The SLK350 is equipped with a 3.5-liter V6 engine producing 300 horsepower and 265 lb-ft of torque, paired with a 7-speed automatic transmission (7G-Tronic). Some owners appreciate the car’s nimble handling, luxurious interior, and distinctive design. Common complaints often revolve around maintenance costs, some electrical quirks, and the firmness of the ride. The SLK was also offered with a SLK280 and SLK55 AMG version.

Engine

3.5L V6 (M272)

• Camshaft Adjuster (Cam Phaser) Failure
  • Description/Symptoms: Ticking or rattling noise at startup, rough idling, loss of power, check engine light illumination. Can be caused by oil starvation or general wear and tear.
  • Solution: Replacement of the camshaft adjusters.
  • Estimated Cost to Fix: $1,500 - $3,000+ (depending on labor and parts)
  • Recalls: None Found
• Balance Shaft Gear Wear (Early Production)
  • Description/Symptoms: Check engine light with codes related to camshaft/crankshaft correlation, engine misfires, rough running. Primarily affects early production M272 engines.
  • Solution: Replacement of the balance shaft. This is a major engine repair requiring extensive labor.
  • Estimated Cost to Fix: $4,000 - $8,000+ (due to the complexity of the repair)
  • Recalls: None Found
• Intake Manifold Tumbler Flap Failure
  • Description/Symptoms: Check engine light, reduced performance, possible whistling noise. The plastic flaps inside the intake manifold can break down.
  • Solution: Replacement of the intake manifold.
  • Estimated Cost to Fix: $800 - $1,500+
  • Recalls: None Found

Transmission

7G-Tronic (722.9)

• Valve Body Issues
  • Description/Symptoms: Harsh or delayed shifting, slipping between gears, erratic shifting behavior. Often caused by wear and tear on the valve body components.
  • Solution: Replacement or refurbishment of the valve body.
  • Estimated Cost to Fix: $1,500 - $3,000+
  • Recalls: None Found
• Torque Converter Failure
  • Description/Symptoms: Shuddering or vibration at low speeds, stalling, transmission slipping.
  • Solution: Replacement of the torque converter.
  • Estimated Cost to Fix: $1,200 - $2,500+
  • Recalls: None Found

Suspension

• Suspension Bushing Wear
  • Description/Symptoms: Clunking noises from the suspension, vague steering, uneven tire wear.
  • Solution: Replacement of worn suspension bushings (control arm bushings, sway bar bushings, etc.).
  • Estimated Cost to Fix: $300 - $1,000+ (depending on which bushings need replacement)
  • Recalls: None Found

Electrical

• Retractable Hardtop Malfunctions
  • Description/Symptoms: The roof gets stuck during operation, fails to open or close completely, error messages on the instrument cluster.
  • Solution: Diagnosis and repair of the hydraulic system (pump, cylinders, hoses), replacement of sensors, or adjustment of the roof mechanism.
  • Estimated Cost to Fix: $500 - $3,000+ (depending on the complexity of the issue)
  • Recalls: None Found
• SAM (Signal Acquisition Module) Failure
  • Description/Symptoms: Various electrical issues, including lighting problems, window malfunctions, central locking failures, and starting problems.
  • Solution: Replacement of the faulty SAM unit and reprogramming.
  • Estimated Cost to Fix: $800 - $1,800+
  • Recalls: None Found

Exterior

• Door Handle Issues
  • Description/Symptoms: The chrome part of the door handle becomes sticky and starts to fall off
  • Solution: Replacement of the door handle
  • Estimated Cost to Fix: $300 - $500+
  • Recalls: None Found

Interior

• Air Conditioning Issues
  • Description/Symptoms: Reduced cooling performance, strange noises from the A/C system, refrigerant leaks.
  • Solution: Diagnosis and repair of the A/C system (compressor replacement, refrigerant recharge, leak repair).
  • Estimated Cost to Fix: $300 - $1,500+
  • Recalls: None Found

Summary

The 2009 Mercedes-Benz SLK350 offers a blend of luxury and performance, but potential buyers should be aware of some common issues. Engine issues, particularly with the balance shaft and camshaft adjusters on earlier models, can lead to expensive repairs. Transmission problems, electrical quirks (especially with the retractable hardtop and SAM module), and suspension wear are also areas to consider. While some repairs may be relatively minor, others can be quite costly, making a pre-purchase inspection by a qualified mechanic highly advisable. The severity of the issues ranges from minor inconveniences to major mechanical failures, with repair costs varying significantly depending on the problem.