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The Mercedes-Benz S-Class W222 S 65 AMG is the pinnacle of luxury and performance, boasting a handcrafted 6.0L V12 twin-turbo engine, cutting-edge technology, and an opulent interior. This flagship sedan represents the best of AMG engineering, offering unmatched power, refinement, and comfort. However, despite its impressive build quality, the S 65 AMG is not immune to mechanical, electrical, and performance-related issues.
Owning a high-performance luxury vehicle like the S 65 AMG comes with the responsibility of understanding its potential problems. This comprehensive guide explores the most common issues associated with the W222 S 65 AMG, their causes, symptoms, and possible solutions. Whether you're a current owner or considering purchasing a used model, being aware of these concerns can help you make informed decisions and maintain the car properly.
Mercedes S-Class W222 S 65 AMG Engine and Performance Issues
The heart of the S 65 AMG is its monstrous 6.0L V12 twin-turbocharged engine, producing an astounding 621 horsepower and 1000 Nm of torque. While this engine is a marvel of engineering, it is also highly complex and prone to certain reliability issues.
Turbocharger and Boost Pressure Failures
Twin turbochargers are essential for the performance of the S 65 AMG, but they are susceptible to failures due to excessive heat, oil contamination, and wastegate actuator malfunctions. Owners have reported issues such as reduced boost pressure, sluggish acceleration, and excessive smoke from the exhaust.
Symptoms of turbo failure include:
Loss of power and delayed throttle response
Whining or high-pitched noises from the turbochargers
Oil leaks around turbocharger connections
Excessive black or blue smoke from the exhaust
Preventative maintenance includes using high-quality synthetic oil, ensuring proper oil change intervals, and avoiding prolonged high-boost conditions that put excessive strain on the turbos. If you experience a loss of boost pressure, inspecting the wastegate actuators and turbo piping for leaks is crucial.
Engine Misfires and Coil Pack Failures
The 6.0L V12 is equipped with two spark plugs per cylinder (24 in total), making ignition system failures relatively common in high-mileage models. A misfiring engine can result from failing ignition coils, worn-out spark plugs, or carbon buildup on the intake valves.
Symptoms of misfires include:
Rough idling and hesitation during acceleration
Check engine light (CEL) illumination
Decreased fuel efficiency and power loss
Engine stuttering under load
Regular replacement of spark plugs and ignition coils can help prevent misfires. Additionally, periodic carbon cleaning of intake valves can maintain optimal engine performance.
Excessive Oil Consumption and Leaks
Many owners have reported that the S 65 AMG consumes more oil than expected, even under normal driving conditions. This issue is often due to worn valve seals, turbo oil leaks, or degraded piston rings.
Signs of excessive oil consumption include:
Frequent need to top up oil between service intervals
Blue smoke from the exhaust (indicative of oil burning)
Visible oil leaks under the car
To prevent engine damage, checking oil levels regularly and addressing leaks early is crucial. In some cases, replacing valve seals or piston rings may be necessary to reduce oil consumption.
Mercedes S-Class W222 S 65 AMG Transmission and Drivetrain Problems
The S 65 AMG is equipped with the robust 7-speed AMG Speedshift Plus automatic transmission, designed to handle the immense torque output of the V12. However, certain transmission-related issues can arise over time.
Harsh Gear Shifts and Transmission Hesitation
Owners have reported transmission hesitations, jerky shifting, and occasional gear slipping. These problems are often linked to transmission software glitches, worn-out valve bodies, or old transmission fluid.
Common symptoms include:
Delayed gear engagement when shifting from park to drive
Harsh upshifts and downshifts
Transmission slipping under acceleration
Warning messages related to the transmission system
Regular transmission fluid changes are essential to maintaining smooth operation. If shifting issues persist, a software update or adaptation reset may be required. In severe cases, replacing the valve body or torque converter may be necessary.
Driveshaft and Differential Wear
Given the immense torque output of the V12, the drivetrain components of the S 65 AMG endure significant stress. Some owners have reported issues with the driveshaft, differential mounts, and rear axles.
Symptoms of drivetrain issues include:
Clunking noises when shifting gears
Vibrations from the rear of the vehicle
Whining noises at high speeds
Regular inspections of the differential and drivetrain components can prevent costly repairs. Replacing worn mounts and using high-quality differential fluid can extend component lifespan.
Mercedes S-Class W222 S 65 AMG Suspension and Ride Quality Issues
The W222 S 65 AMG features the advanced AMG-tuned Magic Body Control suspension, which combines hydraulic dampers and a predictive road-scanning camera system to deliver a smooth ride. However, this system is complex and
prone to failures.
Hydraulic Suspension Leaks and Failures
Unlike the AIRMATIC air suspension found in other S-Class models, the S 65 AMG uses an Active Body Control (ABC) hydraulic suspension system. While it enhances ride comfort and handling, it is known for leaks, worn struts, and failing hydraulic pumps.
Signs of ABC suspension failure include:
Uneven ride height or sagging on one side
Excessive body roll during cornering
Warning messages related to the suspension system
Leaking hydraulic fluid around the suspension struts
If an ABC failure is suspected, it’s essential to diagnose the system early. Replacing worn hydraulic lines and fluid can help prevent pump failure, which is an expensive repair.
Control Arm and Bushing Wear
The heavy weight of the S 65 AMG accelerates wear on suspension control arms and bushings. Over time, these components degrade, leading to increased vibrations and reduced handling precision.
Symptoms include:
Clunking noises over bumps
Poor steering response
Excessive vibration in the cabin
Replacing worn bushings and control arms can restore ride quality and handling performance.
Mercedes S-Class W222 S 65 AMG Electrical and Infotainment System Problems
Given the abundance of electronics in the S 65 AMG, electrical issues are among the most commonly reported problems.
COMAND System Freezing and Glitches
The COMAND infotainment system is known to freeze, lag, or randomly reboot. These issues often stem from software bugs, failing control modules, or corrupted data.
Solutions include performing a system reset, updating the software, or replacing the COMAND head unit if problems persist.
Battery Drain and Charging Issues
The S 65 AMG requires a powerful battery to run its extensive electronics. However, battery drain issues are common, often due to parasitic draws from modules that fail to go into sleep mode.
Signs of battery drain include:
Difficulty starting the vehicle
Warning messages about low voltage
Infotainment system resetting unexpectedly
To prevent battery issues, testing the alternator output and checking for parasitic draws can help identify the cause.
Mercedes S-Class W222 S 65 AMG Braking System Issues
The high-performance braking system in the S 65 AMG is designed to handle the immense power and weight of the vehicle. However, certain issues can arise, especially with prolonged use or aggressive driving.
Premature Brake Wear and Rotor Warping
Due to the weight and performance characteristics of the S 65 AMG, brake pads and rotors wear out faster than in standard S-Class models. Hard braking generates excessive heat, leading to brake fade, rotor warping, and uneven pad wear.
Common symptoms include:
Squeaking or grinding noises when braking
Vibrations in the brake pedal
Increased stopping distances
Regularly inspecting and replacing brake pads and rotors when needed can prevent performance degradation. High-quality aftermarket brake components may offer better durability.
Brake System Warning Lights
Some S 65 AMG owners have reported sudden brake warning messages on the dashboard, often due to issues with the ABS sensors, brake fluid levels, or electronic stability control (ESC). If the warning light appears, a diagnostic scan can reveal potential faults, and sensor replacements or software updates may resolve the issue.
Mercedes S-Class W222 S 65 AMG Cooling System Problems
The cooling system in the S 65 AMG is critical to preventing the powerful V12 engine from overheating. However, due to its complexity and high operating temperatures, issues can develop over time.
Radiator Leaks and Coolant Loss
The radiator is prone to leaks, especially in high-mileage vehicles. Small cracks or weak hose connections can cause coolant loss, leading to overheating and potential engine damage.
Symptoms of a failing radiator include:
Low coolant levels
Visible coolant puddles under the car
Rising engine temperatures
Regularly inspecting the radiator and hoses can prevent catastrophic engine damage. If coolant loss is detected, replacing faulty hoses and sealing leaks promptly is crucial.
Water Pump and Thermostat Failures
A malfunctioning water pump can lead to poor coolant circulation, while a stuck thermostat can cause inconsistent engine temperatures. These failures result in overheating, which can severely damage engine components.
Signs include:
Fluctuating temperature gauge readings
Overheating warnings
Reduced heater performance
Replacing the water pump and thermostat when signs of failure appear is essential for maintaining optimal engine performance.
Mercedes S-Class W222 S 65 AMG Interior and Comfort Issues
The S 65 AMG’s cabin is a showcase of luxury, featuring high-end materials, advanced climate control, and cutting-edge technology. However, some common wear-and-tear issues can diminish the experience.
Leather Seat Wear and Aging
Despite the premium leather used in the S 65 AMG, frequent use can cause seat bolsters to wear prematurely. The driver’s side seat often shows the most wear due to repeated entry and exit.
To preserve the leather, regular conditioning and cleaning with high-quality leather care products are recommended. In severe cases, reupholstering may be required.
Air Conditioning Malfunctions
The multi-zone climate control system in the S 65 AMG can develop issues such as weak airflow, uneven cooling, or complete AC failure. These problems may be caused by refrigerant leaks, clogged cabin air filters, or failing HVAC control modules.
If cooling performance declines, a system inspection should be performed to identify and resolve the underlying issue.
Mercedes S-Class W222 S 65 AMG Exhaust System and Emission Issues
The high-performance exhaust system in the S 65 AMG enhances both sound and efficiency, but certain problems can arise over time.
Catalytic Converter Clogs and Failures
The catalytic converter can become clogged due to excessive carbon buildup, leading to reduced performance and increased emissions.
Signs of a failing catalytic converter include:
Rotten egg smell from the exhaust
Decreased power output
Check engine light activation
Periodic maintenance and using high-quality fuel can prevent premature catalytic converter failure.
Oxygen Sensor Failures
Faulty oxygen sensors can cause inaccurate air-fuel mixture readings, leading to poor fuel economy and increased emissions. Replacing failing sensors promptly can improve overall performance and efficiency.
Mercedes S-Class W222 S 65 AMG Long-Term Maintenance and Ownership Considerations
Given the complexity of the S 65 AMG, long-term ownership requires a proactive approach to maintenance.
Regular Servicing and Inspections
Routine oil changes, brake inspections, and suspension checks are vital to preserving the car’s reliability. Using high-quality fluids and manufacturer-recommended components ensures longevity.
Software Updates and Factory Recalls
Mercedes-Benz frequently releases software updates to improve the functionality of various vehicle systems. Checking for updates and recalls can help address potential factory defects before they cause major issues.
Mercedes S-Class W222 S 65 AMG Conclusion
The Mercedes-Benz S-Class W222 S 65 AMG is a remarkable machine, blending luxury with extreme performance. However, due to its complex engineering and high-performance nature, it is prone to several issues, including turbocharger failures, transmission hesitations, hydraulic suspension leaks, and electronic glitches.
Regular maintenance and proactive repairs are crucial to keeping the S 65 AMG in top condition. By addressing potential problems early and staying up to date with servicing, owners can enjoy a smooth and powerful driving experience.
For expert Mercedes-Benz repairs and servicing, visit European Auto Pro 253 Goodwood Road, Kings Park, 5034 South Australia.
Our specialists are equipped to handle all S 65 AMG maintenance needs, ensuring your vehicle remains in peak condition for years to come.