2018 Mercedes-Benz GLS450

The 2018 Mercedes-Benz GLS450 is a luxury SUV known for its spacious interior, comfortable ride, and elegant styling. The GLS450 is powered by a 3.0-liter turbocharged V6 engine producing 362 horsepower and 369 lb-ft of torque. It is paired with a 9G-TRONIC 9-speed automatic transmission. Some owners praise its smooth ride, luxurious features, and ample cargo space, while others have noted concerns about electronic glitches, maintenance costs, and occasional mechanical issues.

Engine

3.0L Turbocharged V6

• Oil Leaks
  • Description/Symptoms: Oil leaks can occur from various locations, including the valve cover gaskets and oil filter housing. Symptoms include visible oil drips, the smell of burning oil, and low oil levels.
  • Solution: Replacing the leaking gaskets or seals is the typical solution. In some cases, the entire oil filter housing may need replacement.
  • Estimated Cost to Fix: $200 - $1,000+ depending on the location and severity of the leak.
  • Recalls: None Found
• Camshaft Adjuster Issues
  • Description/Symptoms: Some owners report issues with the camshaft adjusters (also known as variable valve timing solenoids). Symptoms include rough idling, decreased engine performance, and potential check engine lights.
  • Solution: Replacement of the faulty camshaft adjuster(s) is usually the solution.
  • Estimated Cost to Fix: $500 - $1,500+
  • Recalls: None Found

Transmission

9G-TRONIC 9-Speed Automatic (725.0 or 725.1)

• Rough Shifting/Hesitation
  • Description/Symptoms: Some owners have reported rough shifting, particularly between certain gears, and hesitation when accelerating. This can manifest as a jerky feeling during gear changes or a delay in response when pressing the accelerator pedal.
  • Solution: In some cases, a software update can resolve the issue. However, in other instances, valve body replacement or complete transmission overhaul/replacement may be necessary.
  • Estimated Cost to Fix: $300 (software update) - $7,000+ (transmission replacement).
  • Recalls: None Found
• Transmission Slipping
  • Description/Symptoms: Owners experience the engine revving high without corresponding acceleration, or a feeling that the transmission is not properly engaging gears.
  • Solution: This often requires a transmission rebuild or replacement.
  • Estimated Cost to Fix: $4,000 - $8,000+
  • Recalls: None Found

Suspension

• Air Suspension Issues (Airmatic)
  • Description/Symptoms: The GLS450 often comes equipped with an air suspension system (Airmatic). Common issues include the compressor failing, air struts leaking, and the vehicle not maintaining the correct ride height. This can manifest as the vehicle sagging on one side or sitting too low overall.
  • Solution: Replacement of the faulty components (compressor, struts, valve block) is required.
  • Estimated Cost to Fix: $1,000 - $3,000+ per strut or for the compressor.
  • Recalls: None Found

Electrical

• COMAND System Malfunctions
  • Description/Symptoms: The COMAND infotainment system can experience a variety of glitches, including freezing, crashing, screen blackouts, and issues with Bluetooth connectivity or navigation.
  • Solution: A software update may resolve some issues. However, in more severe cases, the COMAND unit itself may need replacement.
  • Estimated Cost to Fix: $200 (software update) - $2,000+ (COMAND unit replacement).
  • Recalls: None Found
• Sensor Failures (Parking Sensors, Blind Spot Monitoring, etc.)
  • Description/Symptoms: Faulty sensors can lead to error messages, inoperative safety features (like blind spot monitoring or park assist), and general system malfunctions.
  • Solution: Diagnosis to identify the specific faulty sensor followed by replacement.
  • Estimated Cost to Fix: $200 - $800+ per sensor, depending on location and type.
  • Recalls: None Found
• Battery Drain
  • Description/Symptoms: Some owners report excessive battery drain, leading to difficulty starting the vehicle, especially after periods of inactivity.
  • Solution: Diagnosing and addressing the underlying cause of the drain, which could be a faulty module, a parasitic draw, or a bad battery.
  • Estimated Cost to Fix: $150 (new battery) - $1,000+ (diagnosing and fixing a parasitic draw).
  • Recalls: None Found

Exterior

• Sunroof Issues
  • Description/Symptoms: Some owners report that the sunroof can become stuck, make excessive noise when opening or closing, or leak water.
  • Solution: This may require cleaning and lubricating the tracks, replacing the sunroof motor, or resealing the sunroof assembly.
  • Estimated Cost to Fix: $200 - $1,500+
  • Recalls: None Found

Interior

• Dashboard Delamination/Cracking
  • Description/Symptoms: The dashboard material can sometimes delaminate or crack, particularly in areas exposed to direct sunlight and high temperatures.
  • Solution: Replacement of the entire dashboard or professional repair of the damaged area.
  • Estimated Cost to Fix: $500 (repair) - $3,000+ (replacement).
  • Recalls: None Found
• Seat Motor Failures
  • Description/Symptoms: The power seats can stop adjusting or move erratically.
  • Solution: Replacement of the faulty seat motor or control module.
  • Estimated Cost to Fix: $300 - $1,000+
  • Recalls: None Found

Summary The 2018 Mercedes-Benz GLS450 can present some costly issues to owners. The air suspension, electrical systems, and potential transmission problems are the most concerning. Engine oil leaks are common but often manageable if addressed promptly. The severity of the issues can range from minor inconveniences to major repairs, with costs spanning from a few hundred to several thousand dollars. Pre-purchase inspections by qualified mechanics are highly recommended to identify potential problems before committing to a purchase.