2014 Mercedes-Benz GL450

The 2014 Mercedes-Benz GL450 is a luxury SUV known for its spacious interior, comfortable ride, and powerful engine. It came equipped with a 3.0-liter twin-turbo V6 engine producing 362 horsepower and 369 lb-ft of torque. While highly regarded for its opulent features and smooth handling, some owners have reported recurring problems. Commonly lauded aspects of the GL450 include its elegant design and luxurious amenities, while typical complaints revolve around the expense of repairs and maintenance. In addition to the GL450’s V6, the GL350 BlueTEC was available with a diesel engine, and the GL550 and GL63 AMG offered more powerful V8 options. All models utilized a 7-speed automatic transmission.

Engine

3.0L Twin-Turbo V6 (M276)

• Oil Leaks
  • Description/Symptoms: Oil leaks can develop from various locations, including the valve cover gaskets, oil filter housing, and timing chain cover. Symptoms include visible oil leaks under the vehicle, oil burning smell, and low oil levels.
  • Solution: Replace the leaking gaskets or seals. Thoroughly clean the affected area to prevent future leaks.
  • Estimated Cost to Fix: $200 - $1,500+ depending on the location and severity of the leak.
  • Recalls: None Found
• Turbocharger Issues
  • Description/Symptoms: Whining or whistling noises from the engine bay, reduced engine power, and potentially turbocharger failure. Can be caused by oil starvation, bearing wear, or wastegate malfunctions.
  • Solution: Replace the faulty turbocharger. Check oil lines for blockages and ensure proper lubrication.
  • Estimated Cost to Fix: $1,500 - $3,500+ per turbocharger.
  • Recalls: None Found

Transmission

7G-TRONIC 7-Speed Automatic (722.9)

• Valve Body Issues
  • Description/Symptoms: Hard shifting, erratic shifting, delayed engagement, slipping between gears, or getting stuck in one gear. Can trigger a check engine light and store diagnostic trouble codes (DTCs).
  • Solution: Replacing or rebuilding the valve body. Sometimes, flushing the transmission fluid and replacing the conductor plate can resolve minor issues.
  • Estimated Cost to Fix: $800 - $2,500+.
  • Recalls: None Found
• Torque Converter Failure
  • Description/Symptoms: Shuddering or vibration during acceleration, especially at lower speeds. Can also cause stalling or difficulty engaging gears.
  • Solution: Replace the torque converter. It is often recommended to flush the transmission and replace the filter during this repair.
  • Estimated Cost to Fix: $1,200 - $3,000+.
  • Recalls: None Found

Suspension

• Air Suspension Failure (Airmatic)
  • Description/Symptoms: Vehicle sagging on one or more corners, ride height not adjusting properly, “Visit Workshop” message on the dashboard, and compressor running constantly or not at all. Can be caused by leaks in the air struts, faulty compressor, or a defective valve block.
  • Solution: Replace the leaking air struts or the compressor. Diagnose and repair any leaks in the air lines or valve block.
  • Estimated Cost to Fix: $800 - $2,000+ per air strut; $600 - $1,500+ for the compressor.
  • Recalls: None Found

Electrical

• Battery Drain
  • Description/Symptoms: The car battery drains quickly, especially when the vehicle is parked. Difficulty starting the car, or the car may not start at all. Can be caused by a faulty component that is not shutting off when the vehicle is off.
  • Solution: Perform a parasitic draw test to identify the circuit causing the drain. Repair or replace the faulty component.
  • Estimated Cost to Fix: $100 - $1,000+ depending on the cause of the drain.
  • Recalls: None Found
• SAM (Signal Acquisition Module) Failure
  • Description/Symptoms: Various electrical malfunctions, such as lights not working, wipers not functioning, or issues with the door locks or windows.
  • Solution: Replace the faulty SAM unit. The new unit must be programmed to the vehicle.
  • Estimated Cost to Fix: $500 - $1,500+.
  • Recalls: None Found

Exterior

• Sunroof Issues
  • Description/Symptoms: Sunroof not opening or closing properly, getting stuck, making unusual noises, or leaking water into the cabin. Can be caused by a broken motor, damaged tracks, or clogged drain tubes.
  • Solution: Repair or replace the sunroof motor, tracks, or seals. Clean the drain tubes to prevent water leaks.
  • Estimated Cost to Fix: $300 - $1,200+.
  • Recalls: None Found

Interior

• Navigation/Infotainment System Malfunctions
  • Description/Symptoms: System freezing, crashing, not responding to inputs, or displaying error messages.
  • Solution: Sometimes a software update can resolve these issues. Otherwise, the head unit may need to be replaced.
  • Estimated Cost to Fix: $200 - $2,000+ depending on the repair.
  • Recalls: None Found

Summary

The 2014 Mercedes-Benz GL450 offers a luxurious driving experience but is prone to several common issues that can lead to costly repairs. Engine oil leaks and turbocharger problems are common on the V6 models. The 7-speed transmission is known to develop valve body and torque converter issues. The air suspension system is also a frequent source of problems, often due to leaks in the air struts. Electrical issues, such as battery drains and SAM module failures, can also occur. Interior and exterior issues with the sunroof and infotainment system, round out the list of known issues. While the severity and cost of these issues vary, potential buyers should be aware of these potential problems and factor them into their purchasing decision and budget for future maintenance.