The Mercedes S-Class W221 S 65 AMG is the epitome of luxury and performance, offering unmatched comfort, cutting-edge technology, and a monstrous twin-turbocharged V12 engine. However, despite its reputation as a flagship model, the W221 S 65 AMG is not immune to issues. Owners frequently encounter problems related to its complex mechanical systems, advanced electronics, and high-performance components. This in-depth article explores the common problems of the W221 S 65 AMG, analyzing their causes and providing practical solutions to help maintain this luxurious sedan.
Mercedes S-Class W221 S 65 AMG Engine-Related Problems
The S 65 AMG is powered by the legendary 6.0-liter twin-turbocharged V12 engine (M275), delivering exhilarating performance. While this engine is a masterpiece, it is also prone to specific problems due to its complexity and high power output.
Oil leaks are a well-documented issue with the M275 engine. Over time, gaskets and seals, particularly those around the valve covers and oil pan, can deteriorate and lead to leaks. Symptoms of oil leaks include visible oil stains under the car, a burning oil smell, or low oil levels. The primary cause of this issue is the degradation of rubber gaskets due to heat and pressure. Replacing the faulty gaskets and seals is the only long-term solution. To prevent future leaks, ensure regular oil changes with high-quality synthetic oil and monitor oil levels frequently.
Turbocharger failure is another significant concern for the S 65 AMG. The twin-turbochargers provide the engine's immense power, but they are also susceptible to wear over time. Common symptoms of turbocharger failure include reduced power, increased exhaust smoke, and unusual whining noises during acceleration. The most common cause is oil contamination or insufficient lubrication, which can damage the turbo bearings. Replacing the turbochargers is necessary if they fail, but regular oil changes and using high-quality oil can extend their lifespan.
Misfires are another engine-related problem that can affect the S 65 AMG. Engine misfires result in rough idling, decreased power, and increased fuel consumption. These issues are often caused by failing ignition coils, spark plugs, or clogged fuel injectors. Given the high performance of the engine, these components are subject to significant stress. Replacing worn-out spark plugs and ignition coils and cleaning or replacing fuel injectors can resolve misfire issues. Regular maintenance and using high-quality fuel can also help prevent misfires.
Mercedes S-Class W221 S 65 AMG Transmission Issues
The S 65 AMG is equipped with a robust 5-speed automatic transmission, which is designed to handle the immense torque produced by the V12 engine. However, this transmission can experience problems over time, particularly in older or high-mileage models.
One common problem is delayed or harsh shifting. Owners may notice delays when engaging gears or feel rough transitions between shifts. This issue is often caused by worn-out valve body components or a failing conductor plate. Contaminated or degraded transmission fluid can also exacerbate the problem. To address these issues, the valve body or conductor plate may need replacement, and the transmission fluid and filter should be replaced as part of routine maintenance. Regular fluid changes using the manufacturer-recommended fluid can help prevent such problems.
Torque converter failure is another issue that can affect the transmission. A failing torque converter can cause shuddering during acceleration, difficulty shifting, or even complete transmission failure. This issue is typically caused by wear on the internal components of the torque converter or low transmission fluid levels. Replacing the torque converter is the only solution for this problem. Regularly checking and maintaining transmission fluid levels is crucial to avoid torque converter failure.
Mercedes S-Class W221 S 65 AMG Suspension and Steering Problems
The S 65 AMG is equipped with the Active Body Control (ABC) suspension system, which provides exceptional ride comfort and handling. However, this advanced system is also a frequent source of problems for owners.
One of the most common issues is ABC strut failure. The hydraulic struts in the suspension system are prone to leaks over time, leading to a loss of hydraulic fluid and reduced suspension performance. Symptoms include a sagging suspension, uneven ride height, and warning messages on the dashboard. Strut failure is primarily caused by wear and tear, as well as the high pressure under which the system operates. Replacing the leaking struts and refilling the hydraulic fluid are necessary to restore proper suspension function. Regular inspections and prompt repairs of minor leaks can help prevent complete strut failure.
The ABC pump, which maintains hydraulic pressure in the suspension system, is another component that can fail. When the pump fails, the suspension may become unresponsive or stuck in one position. The failure is often due to internal wear or contamination in the hydraulic fluid. Replacing the pump is required to restore the system’s functionality. Regular fluid changes and using high-quality hydraulic fluid can extend the pump’s lifespan.
Steering problems are also reported by some S 65 AMG owners. These issues are often related to wear in the tie rods or ball joints, which can lead to clunking noises, loose steering, or uneven tire wear. Replacing the worn components is essential to maintain safe and precise steering. Routine inspections of the suspension and steering systems can help identify these problems early.
Mercedes S-Class W221 S 65 AMG Electrical System Problems
The Mercedes S-Class W221 S 65 AMG is packed with advanced electrical systems designed to enhance luxury, convenience, and safety. However, the complexity of these systems often leads to reliability issues as the vehicle ages.
One of the most notable issues is battery drain, a problem frequently reported by S 65 AMG owners. Many owners have experienced situations where their vehicle’s battery dies after being parked for an extended period. This issue is often caused by parasitic drains from malfunctioning electronic components, such as control modules, the COMAND infotainment system, or even the electronic keyless entry system. Diagnosing battery drain requires identifying the specific component responsible for the excessive current draw when the vehicle is off. Once identified, the faulty component must be repaired or replaced. To prevent this issue, owners should ensure that all electronics, such as lights and infotainment systems, are turned off when the vehicle is parked. Regular inspections of the battery and charging system can also help avoid unexpected failures.
The COMAND infotainment system, which manages navigation, audio, and other features, is another source of frustration for many owners. Common problems include screen freezing, non-responsive controls, and software glitches. These issues can occur due to outdated software or hardware failures within the system. In some cases, poor connections or damaged wiring can exacerbate the problem. Addressing this issue often involves performing a software update or replacing faulty components within the infotainment system. Regular updates and ensuring proper handling of the system can reduce the likelihood of these problems.
The S 65 AMG also suffers from issues with its electronic ignition system. The Electronic Ignition Switch (EIS) may fail, resulting in intermittent starting problems or the vehicle failing to recognize the key. Symptoms include a delayed response when turning the key or a complete failure to start. EIS issues are often caused by internal electronic faults or software glitches. Replacing or reprogramming the EIS is usually required to resolve this issue. Additionally, the key fob can develop problems due to battery depletion or internal damage, necessitating battery replacement or key fob repair. Proper care of the key fob and regular battery changes can help mitigate these issues.
Mercedes S-Class W221 S 65 AMG Cooling System Problems
The cooling system in the S 65 AMG plays a crucial role in managing the heat generated by the high-performance V12 engine. However, this system is prone to specific failures that can lead to overheating and significant engine damage if left unaddressed.
Radiator leaks are one of the most commonly reported cooling system problems. The radiator is responsible for dissipating heat from the engine coolant, but over time, it can develop leaks due to corrosion or physical damage. Corrosion is typically caused by the breakdown of coolant or the use of low-quality coolant that allows contaminants to accumulate. Physical damage from debris on the road can also compromise the radiator. Symptoms of a leaking radiator include reduced coolant levels, visible coolant puddles under the car, and engine overheating. Replacing the damaged radiator is often necessary to resolve this issue. Preventative measures include regular coolant flushes and using manufacturer-recommended coolant to prevent corrosion.
Water pump failure is another common issue that affects the cooling system. The water pump circulates coolant throughout the engine, and when it fails, the coolant flow is disrupted, leading to overheating. Symptoms of water pump failure include coolant leaks near the pump, fluctuating engine temperature, and a whining noise from the engine bay. The primary cause of failure is wear on the pump’s internal components, such as the impeller or bearing. Replacing the water pump is the only solution. Routine inspections and timely replacements of worn components can help prevent this problem and ensure the cooling system operates efficiently.
Thermostat failure is also a concern. The thermostat regulates the flow of coolant through the engine, maintaining optimal operating temperature. A faulty thermostat can become stuck in the open or closed position, causing overcooling or overheating, respectively. Symptoms include inconsistent engine temperature and poor heating performance from the climate control system. Replacing the faulty thermostat is necessary to restore proper temperature regulation. Regular monitoring of engine temperature and prompt attention to warning signs can help prevent thermostat-related issues.
Mercedes S-Class W221 S 65 AMG Braking System Problems
The braking system in the S 65 AMG is a critical component designed to handle the immense power of the vehicle. However, certain problems can arise, particularly with the high-performance braking components.
Brake rotor warping is a common issue, especially for owners who drive aggressively or frequently use the vehicle in high-performance conditions. Warped rotors can cause vibrations when braking, reduced braking performance, and uneven wear on the brake pads. The primary cause of rotor warping is excessive heat buildup during braking, which can lead to distortion of the rotor surface. Replacing the warped rotors and installing high-performance brake pads can resolve this issue. Upgrading to rotors designed to handle high heat loads can also prevent warping in the future.
Brake fluid leaks are another issue that can compromise braking performance. Leaks can occur at the brake calipers, master cylinder, or brake lines, leading to a loss of hydraulic pressure. Symptoms include a spongy brake pedal, reduced braking power, and visible fluid near the leaking component. Addressing this problem requires locating and repairing the source of the leak, followed by flushing and refilling the brake fluid. Regular brake system inspections can help identify and address leaks before they become severe.
The electronic parking brake system in the S 65 AMG is another component prone to failure. Issues with the electronic actuators or control module can prevent the parking brake from engaging or releasing properly. Symptoms include warning messages on the dashboard and difficulty engaging or disengaging the parking brake. Fixing this issue involves diagnosing the faulty component and replacing the actuator or reprogramming the control module. Regular use of the parking brake can prevent the actuators from seizing and extend the system’s lifespan.
Mercedes S-Class W221 S 65 AMG Additional Common Problems
Premature rusting, while less common than in older Mercedes models, can still affect the S 65 AMG, particularly in areas with harsh climates or heavy road salt usage. Rust is most likely to appear around the wheel arches, door sills, and trunk edges. Poor drainage design and insufficient rust-proofing during manufacturing are the main culprits. Sanding and repainting affected areas, combined with applying rust inhibitors, can address rust problems. Regular washing, especially during winter, and applying rust-proofing treatments can prevent further corrosion.
Faulty window regulators are another issue that plagues the W221. Over time, the window regulators can fail, causing windows to get stuck or fall into the door. This is often due to wear on the plastic components within the regulator mechanism. Replacing the faulty regulator is necessary to resolve the issue. Gentle operation of the windows can help prolong the life of the regulator.
Conclusion
The Mercedes S-Class W221 S 65 AMG is a remarkable vehicle that offers unparalleled luxury and performance. However, its complexity and high-performance components make it susceptible to certain issues. From engine and transmission problems to suspension, cooling, and electrical system concerns, understanding these common problems is essential for maintaining the vehicle’s performance and longevity. Regular maintenance, timely repairs, and proactive attention to potential issues are crucial to keeping this flagship sedan in top condition.
For expert assistance with diagnosing and repairing any issues with your Mercedes S-Class W221 S 65 AMG, visit European Auto Pro, 253 Goodwood Road, Kings Park, 5034 South Australia. Their experienced technicians specialize in Mercedes-Benz vehicles and are equipped to ensure your car remains in peak condition for years to come.