The Mercedes-Benz S-Class W222 S 500 is a flagship luxury sedan, known for its powerful V8 engine, cutting-edge technology, and unparalleled comfort. However, despite its reputation for excellence, the S 500 is not without its flaws. Owners have reported various mechanical, electrical, and technological issues that can affect reliability and lead to costly repairs.
This comprehensive guide explores the most common problems associated with the W222 S 500, providing insights into their causes, symptoms, and potential solutions. Whether you own an S 500 or are considering purchasing one, understanding these common issues will help you maintain your vehicle and avoid unexpected repair costs.
Mercedes S-Class W222 S 500Engine and Performance Issues
The W222 S 500 is powered by a 4.7L twin-turbocharged V8 engine (M278), delivering an exceptional balance of power and refinement. However, like many high-performance engines, it is prone to certain issues that can impact long-term reliability.
Turbocharger Failures
The M278 engine in the S 500 relies on twin turbochargers to enhance performance and efficiency. Over time, these turbochargers can develop problems due to oil contamination, excessive heat, or actuator malfunctions. Symptoms of failing turbochargers include reduced power, excessive smoke from the exhaust, and a high-pitched whining noise during acceleration.
Turbo failure is often caused by poor oil circulation or carbon buildup. Regular oil changes with high-quality synthetic oil can help prevent premature turbo wear. If performance loss or unusual noises occur, a professional diagnostic check is recommended to assess the health of the turbo system.
Timing Chain and Tensioner Issues
One of the most significant concerns with the M278 engine is timing chain stretch and tensioner failure. The timing chain is responsible for synchronizing the camshaft and crankshaft, and any slack can lead to misfires, rough idling, and severe engine damage.
Common symptoms of timing chain issues include rattling noises on startup, check engine light warnings, and poor acceleration. Replacing the timing chain and tensioners at the first sign of trouble is essential to prevent catastrophic engine failure.
Excessive Oil Consumption
Many S 500 owners have reported unusually high oil consumption between service intervals. This issue is often linked to worn piston rings, valve seals, or turbo seals, leading to oil burning and potential engine damage.
If you notice that the engine requires frequent oil top-ups, a leak-down test can help identify the source of the problem. Addressing oil leaks early and using manufacturer-recommended oil grades can help mitigate excessive oil consumption.
Transmission Problems
The W222 S 500 is equipped with either a 7-speed (7G-Tronic) or a 9-speed (9G-Tronic) automatic transmission, designed for smooth shifts and high efficiency. However, these transmissions are known to develop certain problems over time.
Rough Shifting and Transmission Slippage
Many S 500 owners have experienced rough gear shifts, delayed engagement, or transmission slipping under acceleration. These issues are often caused by degraded transmission fluid, worn clutches, or a malfunctioning transmission control module (TCM).
Symptoms include jerky acceleration, difficulty downshifting, and sudden RPM fluctuations. Regular transmission fluid changes every 60,000 km can prevent many of these issues. In some cases, a software update or adaptation reset may be required to restore smooth shifting.
Torque Converter Shudder
Another common issue is torque converter shudder, which causes noticeable vibrations when accelerating at low speeds. This is often due to deteriorated transmission fluid or internal wear in the torque converter.
A full transmission fluid flush can often resolve the issue. If the problem persists, the torque converter may need to be replaced to restore proper transmission function.
Mercedes S-Class W222 S 500 Suspension and Ride Quality Issues
The S-Class is known for its luxurious ride, largely due to its advanced suspension system. However, components like the AIRMATIC suspension and control arms can develop problems over time.
AIRMATIC Suspension Failures
The S 500 is equipped with AIRMATIC air suspension, which allows for adjustable ride height and adaptive damping. While it provides an exceptionally smooth ride, it is prone to air strut leaks, air compressor failures, and ride height sensor malfunctions.
Common symptoms include:
Uneven ride height
The car sitting too low after being parked overnight
Increased body roll and bouncing over bumps
A failing air strut can put strain on the air compressor, leading to more expensive repairs if not addressed early. If you notice sagging suspension or difficulty adjusting ride height, a full suspension diagnostic is recommended.
Control Arm and Bushing Wear
Another suspension-related issue is premature wear of control arms and bushings. Worn-out control arms can lead to clunking noises, poor handling, and increased road vibrations.
Replacing worn bushings and control arms helps maintain ride quality and handling precision. Regular suspension inspections can help identify potential issues before they worsen.
Mercedes S-Class W222 S 500 Electrical and Technology Issues
The W222 S 500 is packed with advanced technology, but many owners have reported problems with the infotainment system, keyless entry, and battery drain.
COMAND System Malfunctions
The COMAND infotainment system serves as the control hub for navigation, entertainment, and vehicle settings. Common issues include:
System freezes or crashes
Unresponsive touchpad controls
Bluetooth and connectivity failures
These problems are often caused by software glitches or a failing multimedia control module. A system reset or software update can resolve minor issues, but hardware replacements may be necessary for persistent malfunctions.
Keyless-Go and Push-Button Start Failures
Many S 500 owners have encountered issues with the Keyless-Go system, where the car fails to recognize the key fob or the push-button start becomes unresponsive.
Possible causes include:
Weak key fob battery
Faulty keyless entry module
Signal interference from other electronic devices
Replacing the key fob battery is the first step in troubleshooting. If the problem persists, a diagnostic scan may be required to check the keyless entry module.
Battery Drain and Charging System Issues
Battery drain is a frequent complaint among S 500 owners, especially in models equipped with multiple electronic features. Symptoms include:
Slow engine cranking or failure to start
Dashboard warning lights related to battery voltage
Power loss in electronic components like heated seats or ambient lighting
Possible causes of battery drain include:
Faulty alternator
Parasitic drain from malfunctioning electronic modules
Excessive use of power-consuming features when the car is off
Regular battery tests and alternator checks can help prevent unexpected battery failures. If parasitic drain is suspected, a professional diagnostic test can pinpoint the problematic component.
Mercedes S-Class W222 S 500 Cooling System and Overheating Issues
The cooling system in the W222 S 500 plays a crucial role in maintaining engine temperature and preventing overheating. However, various components within this system can develop faults over time, leading to efficiency loss and potential engine damage.
Radiator and Coolant Hose Leaks
Many owners report radiator leaks, which can result in low coolant levels and engine overheating. The plastic components of the radiator can crack due to heat cycles, while rubber coolant hoses may degrade and develop leaks.
Symptoms include:
Visible coolant puddles under the car
Low coolant warning light
Rising engine temperatures
Routine inspection of hoses and the radiator for leaks or cracks can help catch these issues early. If a leak is found, replacing the faulty component promptly can prevent costly engine damage.
Water Pump and Thermostat Failures
The water pump is responsible for circulating coolant through the engine, while the thermostat regulates its temperature. If either component fails, the engine can overheat, leading to serious mechanical damage.
Signs of water pump or thermostat failure include:
Fluctuating temperature gauge readings
Reduced heater performance
Overheating warnings on the dashboard
Replacing a faulty water pump or thermostat at the first sign of trouble is essential to maintain engine health. Regular coolant flushes also help prevent blockages and overheating issues.
Mercedes S-Class W222 S 500 Braking System Problems
The braking system in the S 500 is engineered for optimal performance, but it is not immune to wear and failure.
Premature Brake Wear
The S 500 is a heavy luxury vehicle, which puts significant strain on the braking system. Many owners report that brake pads and rotors wear out faster than expected, leading to frequent replacements.
Symptoms of excessive brake wear include:
Squealing or grinding noises
Vibrations in the brake pedal
Longer braking distances
Using high-quality brake pads and rotors can extend the lifespan of the braking system. Regular inspections ensure that worn components are replaced before they compromise safety.
Brake System Sensor Issues
Some owners experience random brake system warning messages, often due to faulty ABS sensors or brake wear sensors. If the brake warning light appears, a diagnostic scan should be performed to identify the faulty sensor or module.
Mercedes S-Class W222 S 500 Interior Wear and Comfort Issues
The W222 S-Class boasts a luxurious interior, but certain components may experience premature wear or failure.
Seat Bolster Wear and Leather Cracking
The leather upholstery in the S 500 is high quality, but prolonged use can lead to seat bolster wear, especially on the driver’s side. Frequent entry and exit cause stress on the seat’s edges, leading to cracks and wrinkles.
Applying leather conditioner regularly can help maintain the upholstery. In severe cases, reupholstering may be required.
Air Conditioning and Climate Control Problems
Some S 500 models suffer from weak airflow, inconsistent cooling, or complete AC failure. These issues are often caused by:
Clogged cabin air filters
Low refrigerant levels
Malfunctioning HVAC control modules
Routine AC servicing, including refrigerant top-ups and filter replacements, can help prevent these issues.
Mercedes S-Class W222 S 500 Fuel System and Injector Problems
The direct injection system in the S 500 enhances fuel efficiency and performance but is prone to carbon buildup and fuel delivery issues.
High-Pressure Fuel Pump Failure
The high-pressure fuel pump (HPFP) delivers fuel at the required pressure for optimal combustion. Over time, it can wear out, leading to poor acceleration and difficulty starting the car.
Symptoms include:
Hesitation during acceleration
Check engine light related to fuel pressure
Stalling under load
Replacing a failing HPFP early prevents damage to the injectors and engine.
Carbon Buildup on Intake Valves
Direct injection engines are susceptible to carbon deposits forming on intake valves, which can reduce airflow and cause performance issues.
Symptoms include:
Rough idling
Poor throttle response
Increased fuel consumption
Regular intake valve cleaning using walnut blasting or fuel system cleaners helps maintain engine efficiency.
Mercedes S-Class W222 S 500 Exhaust System and Emission Issues
The S 500’s exhaust system includes components such as catalytic converters and oxygen sensors, which can fail over time.
Catalytic Converter Clogging
Excessive carbon buildup in the catalytic converter can lead to restricted exhaust flow and reduced performance. Symptoms include:
Loss of power
Check engine light for emissions system
Unusual exhaust smells
Replacing a clogged catalytic converter is necessary to maintain proper emissions levels and engine efficiency.
Oxygen Sensor Failures
Faulty oxygen sensors can send incorrect readings to the ECU, leading to poor fuel economy and increased emissions. If an oxygen sensor issue is detected, replacing it promptly improves fuel efficiency.
Mercedes S-Class W222 S 500 Long-Term Maintenance and Reliability Considerations
Proper maintenance is key to keeping the Mercedes S 500 running smoothly.
Regular Servicing
Routine oil changes, fluid replacements, and mechanical inspections are essential for longevity. Using manufacturer-recommended fluids and parts helps prevent common failures.
Software Updates and Recalls
Mercedes-Benz frequently releases software updates to improve transmission shifting, infotainment reliability, and electronic system performance. Keeping the vehicle’s software up to date can resolve minor glitches.
Conclusion
The Mercedes-Benz S-Class W222 S 500 is an exceptional luxury sedan, but like any high-performance vehicle, it has its share of common problems. Issues such as turbocharger failures, timing chain wear, transmission roughness, AIRMATIC suspension leaks, and electrical system malfunctions can impact reliability if not addressed in time.
Proactive maintenance, regular servicing, and timely repairs are essential to keep the S 500 in peak condition. By staying informed about potential issues and taking preventive measures, owners can enjoy the full luxury and performance that this flagship model has to offer.
For expert Mercedes-Benz servicing and repairs, visit European Auto Pro 253 Goodwood Road, Kings Park, 5034 South Australia. Our skilled technicians specialize in diagnosing and resolving issues specific to the S 500, ensuring your vehicle remains in optimal condition for years to come.