2009 Mercedes-Benz GL500
The 2009 Mercedes-Benz GL500 (also known as the GL550 in some markets) is a full-size luxury SUV known for its comfortable ride, spacious interior, and robust performance. The GL-Class offers a blend of luxury and capability, making it a popular choice for families and those who need to tow. However, like any vehicle, it has its share of common issues reported by owners. The GL500/GL550 specifically came with a 5.5L V8 engine producing around 382 horsepower and 391 lb-ft of torque. Other engine options in the GL-Class lineup included a 3.0L V6 diesel (GL320/GL350 CDI) and a smaller 4.6L V8 gasoline engine (GL450 in some markets). All engines were paired with a 7-speed automatic transmission (7G-Tronic). Common owner praises include a smooth ride, spaciousness, and powerful engine. Common dislikes revolve around fuel economy, repair costs, and some electrical gremlins.
Engine
5.5L M273 V8
- Camshaft Adjuster Solenoid (Cam Magnet) Failure
- Description/Symptoms: Check engine light, rough idling, reduced engine power. Often caused by oil leaking into the solenoid, causing it to malfunction.
- Solution: Replacement of the faulty camshaft adjuster solenoid.
- Estimated Cost to Fix: $150 - $300+ (including labor)
- Recalls: None Found
- Valve Cover Gasket Leaks
- Description/Symptoms: Oil leaks visible on the engine, burning oil smell, low oil level.
- Solution: Replacement of the valve cover gaskets.
- Estimated Cost to Fix: $300 - $600+ (including labor)
- Recalls: None Found
- Check Engine Light Due to Various Sensor Issues
- Description/Symptoms: Check engine light illuminated, potentially accompanied by various drivability issues depending on the sensor affected (e.g., O2 sensor, MAF sensor).
- Solution: Diagnosis using an OBDII scanner to identify the faulty sensor and subsequent replacement.
- Estimated Cost to Fix: $200 - $500+ (including labor, depending on the sensor)
- Recalls: None Found
Transmission
7G-Tronic 722.9 7-Speed Automatic
- Torque Converter Issues
- Description/Symptoms: Shuddering or vibrations at low speeds, especially when accelerating from a stop. Can also lead to erratic shifting.
- Solution: Replacement or rebuild of the torque converter.
- Estimated Cost to Fix: $1,500 - $3,500+ (including labor)
- Recalls: None Found
- Valve Body Issues
- Description/Symptoms: Hard or delayed shifting, slipping between gears, failure to shift.
- Solution: Replacement or rebuild of the valve body. Sometimes, flushing the transmission fluid and replacing the conductor plate on the valve body can resolve the issue.
- Estimated Cost to Fix: $800 - $2,500+ (including labor)
- Recalls: None Found
- Conductor Plate Failure
- Description/Symptoms: Transmission stuck in limp mode, displaying warning messages on the dashboard, difficulty shifting.
- Solution: Replacement of the conductor plate, often requiring a transmission service (fluid and filter change).
- Estimated Cost to Fix: $600 - $1,200+ (including labor)
- Recalls: None Found
Suspension
- Airmatic Suspension Compressor Failure
- Description/Symptoms: Vehicle sitting low on one or more corners, long time to lift, compressor running constantly, “Airmatic Visit Workshop” message.
- Solution: Replacement of the airmatic suspension compressor.
- Estimated Cost to Fix: $800 - $1,500+ (including labor)
- Recalls: None Found
- Air Strut Leaks
- Description/Symptoms: Vehicle sagging overnight, particularly on one side, rough ride, “Airmatic Visit Workshop” message.
- Solution: Replacement of the leaking air strut(s).
- Estimated Cost to Fix: $800 - $1,800+ per strut (including labor)
- Recalls: None Found
- Airmatic Relay Failure
- Description/Symptoms: Airmatic compressor not turning on, suspension not functioning.
- Solution: Replacement of the airmatic relay.
- Estimated Cost to Fix: $50 - $150+ (including labor)
- Recalls: None Found
Electrical
- Battery Drain Issues
- Description/Symptoms: Car battery frequently dying, requiring jump starts.
- Solution: Diagnosis to identify the parasitic draw (e.g., faulty module, improperly shutting down electronics) and repair/replace the offending component.
- Estimated Cost to Fix: $100 - $1,000+ (depending on the cause)
- Recalls: None Found
- Malfunctioning Power Tailgate
- Description/Symptoms: Power tailgate not opening or closing properly, getting stuck, making unusual noises.
- Solution: Diagnosis and repair/replacement of the tailgate motor, struts, or latch mechanism.
- Estimated Cost to Fix: $300 - $1,000+ (including labor)
- Recalls: None Found
- Faulty Instrument Cluster
- Description/Symptoms: Intermittent or complete failure of the instrument cluster display, incorrect readings, warning lights illuminating randomly.
- Solution: Repair or replacement of the instrument cluster.
- Estimated Cost to Fix: $500 - $1,500+ (including labor)
- Recalls: None Found
Exterior
- Rust on Door Edges and Wheel Arches
- Description/Symptoms: Visible rust forming on the edges of doors, around the wheel arches, and potentially other body panels.
- Solution: Rust repair, including sanding, filling, and repainting.
- Estimated Cost to Fix: $300 - $1,000+ per area (depending on severity and shop rates)
- Recalls: None Found
Interior
- Sunroof Issues
- Description/Symptoms: Sunroof not opening or closing properly, getting stuck, making grinding noises, or leaking.
- Solution: Repair or replacement of the sunroof motor, track, or seals.
- Estimated Cost to Fix: $300 - $1,200+ (including labor)
- Recalls: None Found
- Navigation System Failure
- Description/Symptoms: Navigation system not functioning, screen freezing, GPS errors, inability to update maps.
- Solution: Diagnosis and repair/replacement of the navigation system unit.
- Estimated Cost to Fix: $400 - $1,500+ (including labor)
- Recalls: None Found
Summary
The 2009 Mercedes-Benz GL500/GL550, while a luxurious and capable SUV, is prone to certain issues related to its engine, transmission, air suspension, and electrical systems. The severity of these issues ranges from minor inconveniences (e.g., sensor failures) to more significant and costly repairs (e.g., transmission or air suspension overhaul). Potential buyers should be aware of these common problems and budget accordingly for potential maintenance and repairs. The air suspension and transmission issues are particularly expensive to address. A pre-purchase inspection by a qualified mechanic is highly recommended.