2009 Mercedes-Benz Allegro

The 2009 Mercedes-Benz C-Class (W204) Allegro, while not a specific trim level, generally refers to a C-Class model with a particular set of features or marketing designation in some regions. More commonly known are the C300 and C350 models, the C300 featuring a 3.0-liter V6 engine producing approximately 228 horsepower and 221 lb-ft of torque. Other engine options available for the 2009 C-Class included a 1.8-liter turbocharged four-cylinder and a larger 3.5-liter V6 depending on the trim. Transmission options included a 5-speed automatic and a 7-speed automatic, depending on the engine. Owners often appreciate the C-Class for its blend of luxury, performance, and relatively compact size. Common dislikes include higher maintenance costs compared to non-luxury brands and potential electrical issues. The information below covers all C Class models for the 2009 model year.

Engine

3.0L V6 (C300)

• Oil Leaks from Valve Cover Gaskets
  • Description/Symptoms: Oil leaks are seen around the valve cover area, leading to burning smells and potential oil consumption.
  • Solution: Replace the valve cover gaskets.
  • Estimated Cost to Fix: $300 - $600+
• Camshaft Position Sensor Failure
  • Description/Symptoms: Check engine light, rough idling, stalling, or reduced engine performance.
  • Solution: Replace the faulty camshaft position sensor.
  • Estimated Cost to Fix: $150 - $300+

3.5L V6 (C350)

• Oil Leaks from Valve Cover Gaskets
  • Description/Symptoms: Oil leaks are seen around the valve cover area, leading to burning smells and potential oil consumption.
  • Solution: Replace the valve cover gaskets.
  • Estimated Cost to Fix: $300 - $600+
• Camshaft Position Sensor Failure
  • Description/Symptoms: Check engine light, rough idling, stalling, or reduced engine performance.
  • Solution: Replace the faulty camshaft position sensor.
  • Estimated Cost to Fix: $150 - $300+

Transmission

7-Speed Automatic (7G-Tronic)

• Valve Body Issues
  • Description/Symptoms: Harsh or delayed shifting, slipping between gears, or failure to shift.
  • Solution: Replacement or rebuild of the valve body within the transmission.
  • Estimated Cost to Fix: $800 - $2000+
• Torque Converter Failure
  • Description/Symptoms: Shuddering or vibration at low speeds, stalling, or abnormal noises coming from the transmission area.
  • Solution: Replacement of the torque converter.
  • Estimated Cost to Fix: $1200 - $2500+

Suspension

• Front Control Arm Bushing Wear/Failure
  • Description/Symptoms: Clunking noises from the front suspension, especially when going over bumps, and loose steering.
  • Solution: Replacement of the front control arm bushings or the entire control arm assembly.
  • Estimated Cost to Fix: $300 - $800+ per side
• Sway Bar Link Failure
  • Description/Symptoms: Rattling or clunking noises from the suspension when driving over uneven surfaces.
  • Solution: Replacing the sway bar links.
  • Estimated Cost to Fix: $150 - $400+

Electrical

• SAM (Signal Acquisition Module) Failure
  • Description/Symptoms: Various electrical issues including malfunctioning lights, wipers, or other accessories; can also affect engine starting and running.
  • Solution: Replacement or reprogramming of the affected SAM unit.
  • Estimated Cost to Fix: $500 - $1500+
• EIS (Electronic Ignition Switch) Failure
  • Description/Symptoms: Difficulty starting the vehicle, key not recognized, or complete failure to start.
  • Solution: Replacement of the EIS unit and potentially reprogramming of the keys.
  • Estimated Cost to Fix: $800 - $2000+

Exterior

• Rust on Lower Door Panels/Fenders
  • Description/Symptoms: Visible rust formation on the lower sections of the doors and fenders, particularly in areas exposed to road salt.
  • Solution: Rust repair, panel replacement, and repainting.
  • Estimated Cost to Fix: $500 - $2000+ per panel

Interior

• Sunroof Issues (Failure to Open/Close)
  • Description/Symptoms: Sunroof gets stuck or fails to operate properly, often accompanied by unusual noises.
  • Solution: Repair or replacement of the sunroof motor or mechanism.
  • Estimated Cost to Fix: $300 - $1000+
• Navigation/Infotainment Screen Failure
  • Description/Symptoms: Screen flickering, freezing, or complete failure of the navigation/infotainment system.
  • Solution: Repair or replacement of the screen or the entire head unit.
  • Estimated Cost to Fix: $500 - $2000+

Summary:

The 2009 Mercedes-Benz C-Class, while offering a luxurious driving experience, can be prone to several common issues. The engine and transmission can develop oil leaks and shifting problems, respectively. Suspension components are also known to wear, leading to noise and compromised handling. Electrical issues, particularly with the SAM and EIS modules, can be costly to repair. Interior and exterior issues, such as sunroof malfunctions and rust, further contribute to the overall ownership cost. The severity of these issues ranges from moderate to severe, with repair costs potentially reaching several thousand dollars, especially for transmission or electrical system failures. Addressing these issues proactively can help maintain the vehicle’s reliability and value.