2015 Mercedes-Benz GL450

The 2015 Mercedes-Benz GL450 is a full-size luxury SUV known for its spacious interior, comfortable ride, and advanced features. In 2015, the GL450 was equipped with a 3.0L Turbocharged V6 engine producing 362 horsepower and 369 lb-ft of torque. Other engine options included a 3.0L Turbocharged Diesel V6 (GL350 BlueTEC) and a 4.7L Turbocharged V8 (GL550). All engine options were paired with a 7G-TRONIC 7-speed automatic transmission. Owners often praise the GL450 for its luxurious appointments, smooth ride, and ample cargo space. Common complaints include electronic glitches, high maintenance costs, and occasional suspension issues.

Engine

3.0L Turbocharged V6 (GL450)

• Oil Leaks
  • Description/Symptoms: Oil leaks, often originating from the valve cover gaskets or the oil filter housing. Visible oil drips under the vehicle or a burning oil smell are common.
  • Solution: Replace the leaking gaskets or the entire oil filter housing assembly.
  • Estimated Cost to Fix: $200 - $1500+
  • Recalls: None Found
• Camshaft Adjuster Magnet Failure
  • Description/Symptoms: Engine misfires, rough idling, check engine light. The camshaft adjuster magnets can fail, causing issues with variable valve timing.
  • Solution: Replace the faulty camshaft adjuster magnets.
  • Estimated Cost to Fix: $300 - $800+
  • Recalls: None Found

3.0L Turbocharged Diesel V6 (GL350 BlueTEC)

• AdBlue Heater Failure
  • Description/Symptoms: Check engine light, AdBlue warning message. The AdBlue heater in the Selective Catalytic Reduction (SCR) system can fail, especially in colder climates.
  • Solution: Replace the AdBlue heater or the entire AdBlue tank assembly.
  • Estimated Cost to Fix: $800 - $2000+
  • Recalls: None Found
• Diesel Particulate Filter (DPF) Clogging
  • Description/Symptoms: Reduced engine performance, check engine light, DPF warning message. The DPF can become clogged with soot, especially with frequent short trips.
  • Solution: Perform a forced DPF regeneration, or replace the DPF if severely clogged.
  • Estimated Cost to Fix: $300 - $3000+
  • Recalls: None Found

4.7L Turbocharged V8 (GL550)

• Turbocharger Issues
  • Description/Symptoms: Loss of power, whistling sound from the engine, check engine light. The turbochargers can experience failures such as bearing wear or wastegate malfunction.
  • Solution: Replace or rebuild the faulty turbocharger(s).
  • Estimated Cost to Fix: $2000 - $5000+
  • Recalls: None Found

Transmission

7G-TRONIC 7-Speed Automatic (All Models)

• Torque Converter Failure
  • Description/Symptoms: Shuddering during acceleration, especially at lower speeds. Can also cause a check engine light.
  • Solution: Replace the torque converter.
  • Estimated Cost to Fix: $1500 - $3500+
  • Recalls: None Found
• Valve Body Issues
  • Description/Symptoms: Harsh or delayed shifting, slipping between gears, failure to shift. Valve body problems can be caused by worn solenoids or contamination.
  • Solution: Rebuild or replace the valve body. In some cases, flushing the transmission and replacing the fluid can help.
  • Estimated Cost to Fix: $800 - $2500+
  • Recalls: None Found

Suspension

• Airmatic Suspension Failure
  • Description/Symptoms: Vehicle sagging on one or more corners, compressor running constantly, suspension malfunction warning light. The air springs, compressor, or valve block can fail.
  • Solution: Replace the faulty air spring(s), compressor, or valve block.
  • Estimated Cost to Fix: $800 - $3000+ per component
  • Recalls: None Found
• Air Suspension Compressor Relay Failure
  • Description/Symptoms: Air suspension fails, vehicle sinks to the ground, no response from the air suspension system. Relay located in the rear fuse box is known to fail.
  • Solution: Replace the faulty relay.
  • Estimated Cost to Fix: $10 - $100+
  • Recalls: None Found

Electrical

• Battery Drain
  • Description/Symptoms: Dead battery, requiring frequent jump starts. Parasitic drain caused by a faulty module or electrical component.
  • Solution: Diagnose and repair the parasitic drain. Often involves isolating circuits and testing components.
  • Estimated Cost to Fix: $100 - $1000+
  • Recalls: None Found
• COMAND System Issues
  • Description/Symptoms: Freezing, rebooting, or complete failure of the COMAND infotainment system.
  • Solution: Software updates, or replacement of the COMAND unit.
  • Estimated Cost to Fix: $200 - $2000+
  • Recalls: None Found
• Door Lock Actuator Failure
  • Description/Symptoms: Doors not locking or unlocking with the key fob or interior switch. Faulty door lock actuators.
  • Solution: Replace the faulty door lock actuator.
  • Estimated Cost to Fix: $200 - $500+ per door
  • Recalls: None Found

Exterior

• Sunroof Issues
  • Description/Symptoms: Sunroof not opening or closing properly, getting stuck, or leaking.
  • Solution: Lubricate the sunroof tracks, repair or replace the sunroof motor or regulator.
  • Estimated Cost to Fix: $200 - $1000+
  • Recalls: None Found

Interior

• Seat Heater Failure
  • Description/Symptoms: Seat heaters not working, or only working intermittently.
  • Solution: Replace the heating element or the seat heater control module.
  • Estimated Cost to Fix: $200 - $800+ per seat
  • Recalls: None Found

Summary

The 2015 Mercedes-Benz GL450, while luxurious and comfortable, can suffer from a range of issues. The airmatic suspension is a known area of concern, and various electrical gremlins can appear. Engine oil leaks are also relatively common. While the severity of these issues varies, the repair costs can be significant, making it important to have a pre-purchase inspection performed by a qualified mechanic familiar with Mercedes-Benz vehicles.