2009 Mercedes-Benz R350

The 2009 Mercedes-Benz R350 is a luxury crossover wagon that offered a blend of passenger space, cargo capacity, and a refined driving experience. It came with either a 3.5L V6 engine producing 268 horsepower and 258 lb-ft of torque or a 3.0L turbodiesel V6 engine. Both engines were paired with a 7-speed automatic transmission. People often praised the R350 for its comfortable ride, spacious interior, and available all-wheel drive. Criticisms often revolved around its bulky styling, higher maintenance costs compared to non-luxury vehicles, and some reliability concerns.

Engine

3.5L V6 Gasoline Engine

• Balance Shaft Sprocket Wear
  • Description/Symptoms: Ticking noise from the engine, rough running, check engine light with codes related to camshaft timing. This issue typically affects M272 engines manufactured before 2008, but later models can still experience it.
  • Solution: Replacement of the balance shaft, sprocket, and associated timing components.
  • Estimated Cost to Fix: $2,500 - $4,500+
  • Recalls: None Found
• Camshaft Adjuster Solenoid Failure (Cam Magnets)
  • Description/Symptoms: Check engine light, rough idle, decreased fuel economy, and possible engine misfires.
  • Solution: Replacement of the faulty camshaft adjuster solenoid(s).
  • Estimated Cost to Fix: $200 - $600+
  • Recalls: None Found

3.0L V6 Turbodiesel Engine

• Oil Cooler Seal Leaks
  • Description/Symptoms: Oil leaks, often accumulating near the oil filter housing or on top of the engine. This can lead to a burning oil smell.
  • Solution: Replacement of the oil cooler seals.
  • Estimated Cost to Fix: $800 - $1,500+
  • Recalls: None Found
• Glow Plug Failure
  • Description/Symptoms: Difficult starting, especially in cold weather, rough idle, and a check engine light.
  • Solution: Replacement of the faulty glow plug(s). It is often recommended to replace all glow plugs at the same time.
  • Estimated Cost to Fix: $200 - $500+
  • Recalls: None Found

Transmission

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

• Conductor Plate Failure
  • Description/Symptoms: Erratic shifting, getting stuck in gear, failure to shift, transmission slipping, and a check engine light.
  • Solution: Replacement of the conductor plate, which houses the transmission control unit (TCU).
  • Estimated Cost to Fix: $800 - $1,800+
  • Recalls: None Found
• Valve Body Issues
  • Description/Symptoms: Harsh shifting, delayed engagement, slipping, and general transmission performance issues.
  • Solution: Valve body replacement or rebuild.
  • Estimated Cost to Fix: $1,200 - $3,000+
  • Recalls: None Found

Suspension

• Airmatic Air Suspension Failure (If Equipped)
  • Description/Symptoms: Vehicle sagging on one or more corners, compressor running constantly, “Visit Workshop” message on the dashboard.
  • Solution: Replacement of the faulty air spring(s), air compressor, or valve block.
  • Estimated Cost to Fix: $800 - $2,000+ per air spring; $500 - $1,200+ for the compressor.
  • Recalls: None Found
• Lower Control Arm Bushing Wear
  • Description/Symptoms: Clunking or rattling noises from the front suspension, especially when going over bumps.
  • Solution: Replacement of the lower control arm bushings or the entire control arm.
  • Estimated Cost to Fix: $300 - $800+
  • Recalls: None Found

Electrical

• EIS (Electronic Ignition Switch) Failure
  • Description/Symptoms: Key not recognized, inability to start the car, steering wheel lock malfunction.
  • Solution: Replacement of the EIS module and potentially reprogramming.
  • Estimated Cost to Fix: $800 - $2,000+
  • Recalls: None Found
• SAM (Signal Acquisition Module) Failure
  • Description/Symptoms: Various electrical malfunctions, such as lights not working, wipers malfunctioning, or other electrical components failing.
  • Solution: Replacement of the faulty SAM module and programming.
  • Estimated Cost to Fix: $500 - $1,500+
  • Recalls: None Found

Exterior

• Tail Light Housing Cracking
  • Description/Symptoms: Cracks appearing in the tail light housings, allowing moisture to enter.
  • Solution: Replacement of the tail light housing.
  • Estimated Cost to Fix: $200 - $500+
  • Recalls: None Found

Interior

• Sunroof Issues
  • Description/Symptoms: Sunroof failing to open or close properly, getting stuck, or making excessive noise.
  • Solution: Repair or replacement of the sunroof motor, tracks, or related components.
  • Estimated Cost to Fix: $300 - $1,000+
  • Recalls: None Found

Summary

The 2009 Mercedes-Benz R350, while offering a comfortable and spacious ride, does have some common issues that prospective buyers should be aware of. Engine issues like balance shaft sprocket wear (on the 3.5L V6) and oil cooler leaks (on the diesel) can be expensive to repair. Transmission problems, particularly conductor plate and valve body issues, are also relatively common and costly. The air suspension (if equipped) is another potential source of expensive repairs. Electrical issues, such as EIS or SAM module failure, can also arise. While some issues are minor and relatively inexpensive to fix, others can be quite costly, making a pre-purchase inspection by a qualified mechanic highly recommended.