2012 Mercedes-Benz GL500

The 2012 Mercedes-Benz GL500, also known as the GL550 in some markets, is a full-size luxury SUV offering a blend of comfort, performance, and sophistication. While the GL500 typically came equipped with a 4.7-liter V8 engine producing around 429 horsepower and 516 lb-ft of torque, other engine options for the 2012 GL-Class included a 3.0-liter V6 (GL350 BlueTEC diesel) and a 3.5-liter V6 (GL350). All engines were typically paired with a 7-speed automatic transmission (7G-TRONIC). Owners often praise the GL500 for its spacious cabin, smooth ride, and powerful engine. Some common dislikes include its relatively high running costs and the complexity of its electronic systems.

Engine

4.7L V8 (M278)

• Camshaft Adjuster Failure
  • Description/Symptoms: Rough idling, misfires, loss of power, engine noise (rattling), check engine light. This issue is related to the camshaft adjuster solenoid or the adjuster itself.
  • Solution: Replace the faulty camshaft adjuster and/or solenoid.
  • Estimated Cost to Fix: $1,500 - $3,000+
  • Recalls: None Found
• Oil Leaks (Timing Cover/Valve Cover)
  • Description/Symptoms: Visible oil leaks around the engine, burning oil smell, low oil level.
  • Solution: Replace the timing cover gasket or valve cover gasket.
  • Estimated Cost to Fix: $500 - $1,500+
  • Recalls: None Found

3.0L V6 Diesel (OM642)

• Diesel Particulate Filter (DPF) Issues
  • Description/Symptoms: Reduced engine performance, DPF warning light, potential for engine damage if not addressed. Often caused by short trips where the DPF cannot properly regenerate.
  • Solution: Forced DPF regeneration, DPF cleaning, or DPF replacement.
  • Estimated Cost to Fix: $300 - $2,000+ (depending on the severity and solution)
  • Recalls: None Found
• Oil Cooler Leaks
  • Description/Symptoms: Oil leaks, coolant contamination, overheating. The oil cooler seal often fails.
  • Solution: Replace the oil cooler and seals. This can be a labor-intensive job.
  • Estimated Cost to Fix: $1,000 - $2,500+
  • Recalls: None Found

Transmission

7G-TRONIC (722.9)

• Valve Body Issues
  • Description/Symptoms: Harsh shifting, slipping between gears, delayed engagement, transmission fault codes. Often related to worn solenoids or contaminated fluid.
  • Solution: Valve body replacement or rebuild, transmission fluid flush.
  • Estimated Cost to Fix: $800 - $3,000+
  • Recalls: None Found
• Torque Converter Failure
  • Description/Symptoms: Shuddering at low speeds, transmission slipping, abnormal noises, stalling.
  • Solution: Torque converter replacement.
  • Estimated Cost to Fix: $1,500 - $3,500+
  • Recalls: None Found

Suspension

• Airmatic Suspension Leaks/Failure
  • Description/Symptoms: Vehicle sagging, especially overnight, compressor running excessively, “Visit Workshop” message, rough ride. Can be caused by leaks in the air struts, air lines, or failure of the air compressor.
  • Solution: Replace leaking air struts, repair air lines, replace the air compressor.
  • Estimated Cost to Fix: $800 - $2,500+ per strut (depending on location/dealer), $500-$1500 for compressor.
  • Recalls: None Found

Electrical

• Electronic Stability Program (ESP) Malfunction
  • Description/Symptoms: ESP warning light, reduced traction control, potential ABS issues. Can be caused by a faulty wheel speed sensor, steering angle sensor, or other issues within the ESP system.
  • Solution: Diagnose the root cause (scan for codes) and replace the faulty component.
  • Estimated Cost to Fix: $200 - $1,000+ depending on the component.
  • Recalls: None Found
• Battery Drain Issues
  • Description/Symptoms: Dead battery, difficulty starting the vehicle. Could be caused by a parasitic drain from a faulty module or component.
  • Solution: Diagnose and repair the source of the parasitic drain. This can be a time-consuming process.
  • Estimated Cost to Fix: $100 - $800+ (depending on the complexity of the issue)
  • Recalls: None Found

Exterior

• Sunroof Issues
  • Description/Symptoms: Sunroof not opening or closing properly, getting stuck, or making excessive noise. Problems with the sunroof motor or track are common.
  • Solution: Repair or replace the sunroof motor or track.
  • Estimated Cost to Fix: $300 - $1,200+
  • Recalls: None Found

Interior

• COMAND System Malfunctions
  • Description/Symptoms: Screen freezing, system crashing, navigation issues, audio problems. Software glitches or hardware failures within the COMAND unit are common.
  • Solution: Software update, COMAND unit repair or replacement.
  • Estimated Cost to Fix: $200 - $2,000+
  • Recalls: None Found
• Power Seat Problems
  • Description/Symptoms: Seat not moving in one or more directions, clicking noises, getting stuck. Can be caused by a faulty seat motor, switch, or wiring.
  • Solution: Repair or replace the faulty seat motor, switch, or wiring.
  • Estimated Cost to Fix: $200 - $800+
  • Recalls: None Found

Summary:

The 2012 Mercedes-Benz GL500, while a luxurious and capable SUV, can be prone to several issues. Engine problems, particularly related to camshaft adjusters and oil leaks in the V8 and DPF issues in the diesel, can be expensive to address. Transmission issues, especially with the valve body, are also common. The Airmatic suspension is a known weak point, and electrical glitches can add to the ownership costs. Overall, potential buyers should be aware of these common issues and factor in the potential for higher repair costs when considering this vehicle. Addressing issues early can help prevent them from escalating into more significant and expensive problems.