2012 Mercedes-Benz GL350

The 2012 Mercedes-Benz GL350 BlueTEC 4MATIC is a full-size luxury SUV known for its spacious interior, comfortable ride, and fuel efficiency relative to its size thanks to its diesel engine. The GL350 BlueTEC is equipped with a 3.0-liter turbocharged diesel V6 engine producing 240 horsepower and 455 lb-ft of torque. Other engine options for the 2012 GL-Class include the GL450 with a 4.6-liter V8, the GL550 with a 4.6-liter twin-turbo V8, and the high-performance GL63 AMG with a 5.5-liter twin-turbo V8. All models are equipped with a 7-speed automatic transmission. Owners generally appreciate the GL-Class for its luxurious features, smooth ride, and towing capacity. Some common complaints include higher than average repair costs, occasional electrical glitches, and concerns about the reliability of the air suspension system.

Engine

3.0L Turbo Diesel V6 (GL350 BlueTEC)

• Oil Cooler Seal Leak
  • Description/Symptoms: Oil leak near the front of the engine. Visible oil accumulation on the lower engine components. Oil may drip onto the ground.
  • Solution: Replace the oil cooler seals.
  • Estimated Cost to Fix: $500 - $1,000+
  • Recalls: None Found
• AdBlue Heater Failure
  • Description/Symptoms: Check engine light, diagnostic trouble codes (DTCs) related to the AdBlue (diesel exhaust fluid) system, specifically the heater. Potential limp mode or restricted engine performance.
  • Solution: Replace the AdBlue heater.
  • Estimated Cost to Fix: $800 - $1,500+
  • Recalls: None Found
• Glow Plug Failure
  • Description/Symptoms: Hard starting, especially in cold weather. Check engine light. Diagnostic Trouble Codes related to the glow plugs.
  • Solution: Replace faulty glow plug(s).
  • Estimated Cost to Fix: $200 - $500+
  • Recalls: None Found

Transmission

7-Speed Automatic (7G-Tronic)

• Torque Converter Failure
  • Description/Symptoms: Shuddering or vibration during acceleration, particularly at low speeds. Transmission slipping. Harsh or delayed shifts.
  • Solution: Replace the torque converter.
  • Estimated Cost to Fix: $2,000 - $4,000+
  • Recalls: None Found
• Valve Body Issues
  • Description/Symptoms: Erratic shifting, harsh shifts, slipping between gears, getting stuck in a gear, or failure to shift. Check engine light may be illuminated.
  • Solution: Replace or rebuild the valve body.
  • Estimated Cost to Fix: $1,500 - $3,000+
  • Recalls: None Found

Suspension

• Air Suspension Compressor Failure
  • Description/Symptoms: Vehicle sagging or uneven ride height. The suspension fails to adjust properly. “Visit Workshop” message appears on the instrument cluster. Loud compressor noise.
  • Solution: Replace the air suspension compressor.
  • Estimated Cost to Fix: $800 - $1,500+
  • Recalls: None Found
• Air Spring Leaks
  • Description/Symptoms: Vehicle sagging, especially overnight. A hissing sound coming from the air springs. Uneven ride height.
  • Solution: Replace the leaking air spring(s).
  • Estimated Cost to Fix: $700 - $1,200+ per air spring
  • Recalls: None Found

Electrical

• EIS (Electronic Ignition Switch) Failure
  • Description/Symptoms: Key not recognized. Inability to start the vehicle. Steering wheel not unlocking.
  • Solution: Replace the EIS module. Programming may be required.
  • Estimated Cost to Fix: $800 - $1,500+
  • Recalls: None Found
• SAM (Signal Acquisition Module) Failure
  • Description/Symptoms: Various electrical issues, such as lights not working, wipers malfunctioning, or other electronic components failing to operate correctly.
  • Solution: Replace the faulty SAM unit. Programming may be required.
  • Estimated Cost to Fix: $700 - $1,500+
  • Recalls: None Found

Exterior

• No Issues Found

Interior

• Sunroof Issues
  • Description/Symptoms: Sunroof not opening or closing properly, getting stuck, or making unusual noises.
  • Solution: Repair or replace sunroof motor, rails, or associated components.
  • Estimated Cost to Fix: $300 - $1,000+
  • Recalls: None Found

Summary

The 2012 Mercedes-Benz GL350 BlueTEC offers a blend of luxury and utility, but it is important to be aware of some potential issues. The most common problems revolve around the engine (oil leaks, AdBlue system, glow plugs), transmission (torque converter, valve body), air suspension (compressor and spring failures), and electrical components (EIS, SAM modules). While some repairs may be relatively minor, others can be quite costly, particularly those involving the air suspension or transmission. Prospective buyers should have a pre-purchase inspection performed by a qualified mechanic familiar with Mercedes-Benz vehicles to identify any potential issues before making a purchase.