The Mercedes-Benz S-Class W222 S 350 represents the pinnacle of luxury, offering cutting-edge technology, unparalleled comfort, and exceptional performance. However, like any vehicle, it is not without its flaws. Owners of the W222 S 350 have reported several recurring issues that can impact the car’s reliability and performance. In this in-depth article, we’ll explore the most common problems associated with the W222 S 350, their causes, and effective solutions.
Mercedes S-Class W222 S 350 Engine Performance Issues
The Mercedes S 350 is equipped with a powerful 3.0-liter V6 diesel engine that delivers smooth and refined performance. Despite its reputation for reliability, the engine is known to suffer from specific issues over time. Two of the most commonly reported problems are oil leaks and turbocharger failures.
Oil leaks are a frequent concern for W222 S 350 owners, with leaks often originating from the valve cover gasket, oil pan gasket, or turbo oil lines. Over time, these gaskets and seals can degrade due to heat and pressure, losing their ability to maintain a proper seal. Symptoms of oil leaks include visible oil stains under the vehicle, a burning oil smell, or reduced oil levels. To address oil leaks, it is necessary to replace the damaged gaskets or seals. Preventative maintenance, such as regular oil changes using high-quality synthetic oil, can reduce the likelihood of leaks developing.
Turbocharger failures are another potential issue with the S 350’s diesel engine. The turbocharger is critical for enhancing engine power and efficiency by compressing incoming air. A failing turbocharger can result in reduced power, increased fuel consumption, and excessive smoke from the exhaust. Common causes of turbo failure include oil contamination, lack of lubrication, and excessive wear on the turbine or compressor. Resolving this problem involves replacing the turbocharger or rebuilding it if the damage is not severe. Regular oil changes and ensuring the turbocharger is adequately lubricated can help prevent premature failure.
Mercedes S-Class W222 S 350 Transmission Problems
The 7G-Tronic automatic transmission in the W222 S 350 is generally regarded as reliable, but some owners have reported issues as the vehicle ages. The most common problems include rough shifting, delayed engagement, and occasional gear slipping.
Rough shifting and delayed engagement can make driving the S 350 less smooth and enjoyable. These issues are often caused by worn valve bodies or solenoids within the transmission. Old or contaminated transmission fluid can also exacerbate the problem by reducing hydraulic pressure. Replacing the valve body or solenoids is often required to resolve the issue, along with a complete transmission fluid and filter replacement. Routine maintenance, such as changing the transmission fluid at recommended intervals, can prevent these problems from arising.
Gear slipping is another reported issue and is often caused by internal clutch wear or a failing conductor plate. When the clutches within the transmission wear out, they struggle to maintain grip, leading to gear slipping under load. Rebuilding or replacing the affected components is necessary to restore proper transmission function. Addressing minor transmission issues early can help prevent more extensive and costly repairs down the line.
Mercedes S-Class W222 S 350 Air Suspension System Problems
The W222 S 350 features Mercedes-Benz’s AIRMATIC air suspension system, which delivers an exceptionally smooth ride and allows for adjustable ride height. However, this system is prone to failures, particularly as the vehicle accumulates mileage.
One of the most common issues with the AIRMATIC system is air strut failure. Over time, the rubber components of the air struts can develop leaks, leading to a loss of air pressure. Symptoms of air strut failure include a sagging suspension, uneven ride height, or a warning message on the dashboard. In many cases, the air compressor has to work harder to compensate for the leak, which can lead to premature compressor failure. Replacing the leaking air strut and inspecting the compressor for damage are necessary steps to resolve the issue. Regularly checking for early signs of wear, such as minor air leaks or unusual noises, can help avoid complete suspension failure.
Compressor failure is another issue that affects the AIRMATIC system. The compressor is responsible for maintaining the air pressure in the suspension system, and when it fails, the suspension may collapse entirely. Compressor failure is often caused by overuse due to air leaks or electrical faults. Replacing the compressor is typically required to restore proper suspension function. Upgrading to a high-quality aftermarket compressor can provide improved durability and performance.
Mercedes S-Class W222 S 350 Electrical System Glitches
The W222 S 350 is packed with advanced electronic systems, from its infotainment and driver-assistance features to its climate control and lighting. However, these systems are complex and can sometimes malfunction, leading to various electrical problems.
One of the most common issues reported by owners is with the Command infotainment system. Problems include freezing screens, non-responsive controls, and audio system failures. These glitches are often caused by outdated software, hardware failures, or electrical faults. Updating the software or replacing the malfunctioning hardware components can resolve these issues. Ensuring the system is updated regularly and handled carefully can reduce the likelihood of future problems.
Battery drain is another frequently reported electrical issue. Many W222 S 350 owners have experienced unexplained battery drain, leaving them with a dead battery after the car is parked for extended periods. This issue is often caused by parasitic draws from faulty components, such as control modules, sensors, or the keyless entry system. Diagnosing battery drain requires identifying the source of the parasitic draw and repairing or replacing the faulty component. Turning off unnecessary features and ensuring that all electronics are switched off before leaving the vehicle can help prevent battery drain.
Mercedes S-Class W222 S 350 Cooling System Problems
The cooling system in the Mercedes S-Class W222 S 350 is crucial for maintaining optimal engine temperature and preventing overheating. However, certain issues are commonly reported by owners, particularly as the vehicle ages or if regular maintenance has been neglected. Two of the most prevalent cooling system problems include radiator leaks and thermostat or water pump failures.
Radiator leaks are a significant concern for S 350 owners, with symptoms such as visible coolant puddles under the car, a gradual loss of coolant, or engine overheating. The radiator’s primary function is to dissipate heat from the engine coolant, but over time, it can develop leaks due to corrosion or physical damage. Corrosion is often the result of using low-quality or improperly mixed coolant, which allows rust and contaminants to accumulate inside the radiator. Additionally, road debris can cause small punctures in the radiator’s surface. Addressing radiator leaks involves repairing small cracks with a sealant or replacing the radiator entirely in more severe cases. To prevent radiator issues, regular coolant flushes using high-quality, manufacturer-recommended coolant are essential. Inspections should also include checking for physical damage to the radiator.
Thermostat and water pump failures are also common cooling system issues. The thermostat regulates the flow of coolant through the engine, while the water pump ensures its continuous circulation. When the thermostat fails, it can become stuck open or closed, causing the engine to run too cold or overheat, respectively. Similarly, a failing water pump may result in insufficient coolant circulation, leading to overheating. Symptoms of these issues include fluctuating engine temperatures, coolant leaks, or a whining noise from the engine bay. Replacing the faulty thermostat or water pump is necessary to restore the cooling system’s functionality. Regular maintenance, including inspecting hoses and coolant levels, can help detect early signs of these problems and prevent costly repairs.
Mercedes S-Class W222 S 350 Interior and Comfort Problems
The W222 S 350 is renowned for its luxurious interior, but even high-end features can experience wear and tear over time. Owners frequently report problems with the power seat adjusters, climate control system, and ambient lighting.
Power seat adjuster malfunctions are a common complaint among S 350 owners. The vehicle’s electrically adjustable seats allow for precise customization of seating positions, but over time, the motors or switches that control these adjustments can fail. Symptoms include seats becoming stuck in one position or responding sluggishly to commands. The primary causes of these issues are wear and tear on the motors, electrical faults, or damaged wiring. Repairs typically involve replacing the faulty motor or switch, while addressing wiring problems may require professional diagnosis. To minimize the risk of failure, it’s advisable to handle seat adjustments gently and avoid forcing the controls when they resist movement.
The climate control system in the W222 is another source of frustration for some owners. Problems such as inconsistent airflow, insufficient cooling or heating, and strange noises from the vents are commonly reported. These issues are often linked to a failing blower motor, clogged cabin air filters, or refrigerant leaks. In some cases, the climate control module itself may malfunction, leading to erratic behavior. Repairs may involve cleaning or replacing air filters, recharging the refrigerant, or replacing the blower motor or control module. Routine maintenance, such as replacing cabin air filters and checking refrigerant levels, can help keep the climate control system functioning optimally.
Ambient lighting, a hallmark of the S-Class interior, can also develop issues over time. Some owners report dim or flickering lights or sections of the ambient lighting failing altogether. These problems are typically caused by faulty wiring or LED strips. Replacing the damaged components usually resolves the issue. To ensure the longevity of the ambient lighting system, it’s important to avoid tampering with the wiring or overloading the electrical system with aftermarket modifications.
Mercedes S-Class W222 S 350 Premature Rusting
Rust is an issue that affects many Mercedes models, and the W222 S 350 is no exception. While the S-Class benefits from improved rust protection compared to earlier generations, some owners still report premature rusting, particularly in areas with harsh winters or frequent road salt exposure. Common areas where rust tends to develop include the wheel arches, door sills, and the underside of the vehicle.
The primary cause of rust is prolonged exposure to moisture, road salt, and debris, combined with insufficient drainage in certain parts of the vehicle. Even small scratches or chips in the paint can expose the underlying metal to rust. Addressing rust involves sanding down the affected areas, applying a rust inhibitor, and repainting the surface to restore its appearance and protection. Preventing rust requires regular washing, especially during winter months, and applying an underbody rust-proofing treatment. Waxing the vehicle periodically can also help protect the paint and reduce the risk of rust development.
Mercedes S-Class W222 S 350 Suspension Issues
While the AIRMATIC air suspension system in the W222 S 350 offers exceptional ride quality, it is not without its vulnerabilities. In addition to air strut and compressor failures, owners also report problems with suspension sensors and control modules.
Suspension sensors are responsible for monitoring the vehicle’s ride height and adjusting the air suspension accordingly. When these sensors fail, the vehicle may display an incorrect ride height, or the suspension may not adjust properly, resulting in an uneven or uncomfortable ride. Sensor failure is often caused by exposure to dirt, moisture, or physical damage. Replacing the faulty sensor is usually necessary to restore proper suspension function.
The suspension control module is another component that can develop faults. This module communicates with various sensors and components to manage the air suspension system. Electrical faults or software glitches in the control module can lead to erratic suspension behavior, warning lights on the dashboard, or failure of the system to respond to adjustments. Reprogramming or replacing the control module is the most effective solution. Regular inspections of the suspension system can help identify potential issues early and ensure reliable performance.
Conclusion
The Mercedes S-Class W222 S 350 is a remarkable luxury vehicle, but like any car, it has its share of common problems. From engine and transmission issues to electrical glitches, air suspension failures, and interior concerns, these problems can impact the ownership experience. However, with proper maintenance and timely repairs, many of these issues can be managed effectively, ensuring the S 350 remains a reliable and enjoyable car to drive.
For expert assistance with diagnosing and repairing any issues with your Mercedes S-Class W222 S 350, visit European Auto Pro, 253 Goodwood Road, Kings Park, 5034 South Australia. Their skilled technicians specialize in Mercedes-Benz vehicles and can help keep your S-Class in impeccable condition.