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2006 Mercedes-Benz R350

The 2006 Mercedes-Benz R350 is a luxury crossover/wagon that aimed to blend the comfort of a sedan with the practicality of an SUV. The R350 primarily came with a 3.5L V6 engine producing 268 horsepower and 258 lb-ft of torque, paired with a 7-speed automatic transmission (7G-TRONIC). Some owners appreciated its spacious interior, comfortable ride, and elegant styling. Common dislikes included the vehicle’s hefty size, potential for expensive repairs, and sometimes quirky electronics. Other engines include a 3.0L V6 diesel engine (R320 CDI) that produces 215 horsepower and 398 lb-ft of torque.

Engine

3.5L V6

  • Balance Shaft Gear Wear
    • Description/Symptoms: A common issue with the M272 engine (3.5L V6) involves premature wear of the balance shaft gear. This can cause rough running, misfires, and eventually a check engine light. The noise can be heard as a whine. Diagnostic trouble codes (DTCs) related to camshaft timing are often present.
    • Solution: Replacement of the balance shaft, which is a labor-intensive job as it requires significant engine disassembly.
    • Estimated Cost to Fix: $3,000 - $5,000+
    • Recalls: None Found
  • Intake Manifold Flap Motor Failure
    • Description/Symptoms: The intake manifold on the M272 engine utilizes flaps to optimize airflow. The flap motor or the manifold itself can fail, resulting in reduced performance, poor fuel economy, and a check engine light.
    • Solution: Replacement of the intake manifold assembly or the flap motor, depending on the specific failure.
    • Estimated Cost to Fix: $800 - $1,500
    • Recalls: None Found

3.0L V6 Diesel (R320 CDI)

  • Oil Cooler Leaks
    • Description/Symptoms: The oil cooler seal is prone to leaking. Leaking oil will drip onto the ground and potentially cause a burning smell.
    • Solution: Replace the oil cooler seal
    • Estimated Cost to Fix: $800 - $1,200
    • Recalls: None Found
  • Diesel Particulate Filter (DPF) Issues
    • Description/Symptoms: DPF can become clogged over time, particularly with short trips or low-speed driving. This can lead to reduced performance, increased fuel consumption, and eventually a check engine light.
    • Solution: Forced regeneration of the DPF, replacement of the DPF, or cleaning of the DPF (if possible).
    • Estimated Cost to Fix: $300 - $2,000+ (depending on the solution)
    • Recalls: None Found

Transmission

7G-TRONIC (722.9)

  • Torque Converter Issues
    • Description/Symptoms: Some owners have reported issues with the torque converter in the 7G-TRONIC transmission, leading to shuddering, hesitation during acceleration, or rough shifting.
    • Solution: Replacement of the torque converter or, in some cases, a complete transmission rebuild.
    • Estimated Cost to Fix: $1,500 - $4,000+
    • Recalls: None Found
  • Valve Body Problems
    • Description/Symptoms: Malfunctioning valve bodies are another known issue in the 7G-TRONIC transmission. This can manifest as harsh shifting, delayed engagement, or failure to shift at all.
    • Solution: Replacement or rebuilding of the valve body.
    • Estimated Cost to Fix: $800 - $2,000
    • Recalls: None Found

Suspension

  • Air Suspension Failure (If Equipped)
    • Description/Symptoms: The R350 can be equipped with Airmatic air suspension. The air struts can leak, leading to a sagging vehicle, particularly overnight. The air compressor can also fail. Dashboard warnings are usually present.
    • Solution: Replacement of the leaking air struts or the air suspension compressor.
    • Estimated Cost to Fix: $800 - $2,000+ per strut; $500 - $1,200 for the compressor.
    • Recalls: None Found
  • Rear Air Springs
    • Description/Symptoms: Rear air springs may wear down over time. This can cause the rear of the vehicle to sag, especially when parked.
    • Solution: Replacement of the air springs
    • Estimated Cost to Fix: $600 - $1,000+
    • Recalls: None Found

Electrical

  • SAM (Signal Acquisition Module) Issues
    • Description/Symptoms: The SAM controls various electrical functions. The front or rear SAM units can fail, leading to issues with lighting, wipers, power windows, and other electrical components.
    • Solution: Replacement of the faulty SAM unit. Programming may be required.
    • Estimated Cost to Fix: $500 - $1,500
    • Recalls: None Found
  • EIS (Electronic Ignition Switch) Failure
    • Description/Symptoms: The EIS can fail, preventing the car from starting. This is a relatively common issue on Mercedes-Benz vehicles of this era.
    • Solution: Replacement of the EIS and potentially reprogramming of the key.
    • Estimated Cost to Fix: $800 - $1,800+
    • Recalls: None Found
  • Sunroof Motor Failure
    • Description/Symptoms: The sunroof motor may fail or become weak, resulting in the sunroof not opening or closing properly.
    • Solution: Replacement of the sunroof motor.
    • Estimated Cost to Fix: $300 - $800
    • Recalls: None Found

Exterior

  • Tail Light Assembly Issues
    • Description/Symptoms: The tail light assemblies can develop cracks, or the bulbs can frequently burn out due to electrical issues within the assembly.
    • Solution: Replacement of the tail light assembly.
    • Estimated Cost to Fix: $200 - $500 per assembly
    • Recalls: None Found

Interior

  • Command System Issues
    • Description/Symptoms: Problems can arise with the COMAND system (Mercedes’ infotainment system), including screen failures, navigation malfunctions, or Bluetooth connectivity issues.
    • Solution: Repair or replacement of the COMAND unit.
    • Estimated Cost to Fix: $500 - $2,000+
    • Recalls: None Found

Summary

The 2006 Mercedes-Benz R350, while offering luxury and practicality, is prone to several issues that can result in significant repair costs. Engine-related problems, particularly with the balance shaft on the 3.5L V6, and transmission issues with the 7G-TRONIC transmission, are common and expensive. Air suspension failures, if equipped, can also be costly. Electrical gremlins are also a common occurrence. Prospective buyers should be aware of these potential issues and budget accordingly, or seek a pre-purchase inspection by a qualified Mercedes-Benz mechanic. While maintenance costs can be high, addressing these issues proactively can help extend the life and enjoyment of the vehicle.

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