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The Mercedes G-Class W463 G 65 AMG is one of the most powerful and luxurious SUVs ever produced. Equipped with a 6.0L twin-turbocharged V12 engine, it delivers an exhilarating driving experience.
However, this vehicle is not without its issues. While it is known for durability and performance, owners have reported a number of mechanical, electrical, and structural problems over time.
For those considering ownership, or for current G 65 AMG drivers looking to maintain their vehicle, understanding the most common problems is essential.
Let’s take an in-depth look at the key challenges associated with this high-performance luxury SUV.
Mercedes G-Class W463 G 65 AMG Engine and Turbocharger Issues
The M279 6.0L V12 twin-turbo engine in the G 65 AMG is a marvel of engineering, but like any high-performance motor, it comes with its own set of challenges.
One of the most common complaints among owners is turbocharger failure. The G 65 AMG features two turbochargers, which work together to generate immense power.
However, excessive heat, oil contamination, or worn-out seals can cause these turbos to fail.
When this happens, owners may notice a loss of power, excessive smoke from the exhaust, or a loud whining noise from the engine bay.
Another frequent issue is intercooler leaks, which reduce the efficiency of the turbo system. A leaking intercooler can cause reduced boost pressure, leading to sluggish acceleration and increased fuel consumption.
Additionally, vacuum lines and wastegate actuators tend to wear out over time, affecting turbo performance and leading to boost pressure inconsistencies.
Another well-documented problem is carbon buildup in the intake system. Due to direct fuel injection, carbon deposits form inside the intake valves, causing rough idling, power loss, and misfires.
Regular intake cleaning services can help prevent this issue, but if neglected, it can lead to expensive repairs.
Mercedes G-Class W463 G 65 AMG Cooling System Problems
The G 65 AMG produces immense power, which generates excessive heat. As a result, the cooling system is under constant stress.
One of the most frequent complaints is radiator leaks. The radiator, made with a mix of aluminum and plastic, tends to degrade over time, leading to coolant leaks.
If not addressed promptly, a leaking radiator can cause overheating, which may result in severe engine damage.
Another related issue is water pump failure. The water pump is responsible for circulating coolant throughout the engine, but over time, its bearings and seals can wear out.
A failing water pump often leads to engine overheating, coolant loss, and an illuminated check engine light.
Owners also report coolant hose deterioration. Due to the high operating temperatures of the V12 engine, rubber hoses tend to harden and crack, leading to slow coolant leaks.
Additionally, the thermostat is known to fail, sometimes sticking in the closed position, which prevents coolant circulation and results in overheating.
Mercedes G-Class W463 G 65 AMG Transmission and Drivetrain Issues
The Mercedes G 65 AMG is equipped with a 7-speed automatic transmission (7G-Tronic), which is generally reliable but can develop problems over time.
One of the most common issues is rough shifting. Some owners report delayed gear engagement, slipping gears, or jerky shifts, which can be caused by worn-out transmission mounts, software glitches, or valve body failures.
Another frequent complaint is torque converter failure. The torque converter is responsible for smoothly transferring power from the engine to the wheels, but if it fails, symptoms such as shuddering, hesitation, or complete loss of power may occur.
Repairing or replacing a torque converter can be expensive, and the issue often worsens if ignored.
Drivetrain problems extend beyond the transmission. Since the G 65 AMG is a full-time 4WD vehicle, its transfer case and differentials are constantly engaged.
Many owners report fluid leaks from the transfer case, which, if left unattended, can lead to gear wear and eventual failure.
Additionally, differential noise, such as whining or grinding, can indicate low fluid levels or worn-out bearings.
Another known problem is driveshaft vibration. This can be caused by failing universal joints (U-joints) or worn-out driveshaft support bearings.
If left unchecked, driveshaft imbalance can lead to further drivetrain damage and expensive repairs.
Mercedes G-Class W463 G 65 AMG Suspension and Steering Concerns
The G 65 AMG features an air suspension system that provides a comfortable and adjustable ride. However, air suspension components are prone to failure, particularly air struts and the compressor.
A common issue is air strut leaks, which cause the vehicle to sag on one side or lower unevenly. If the suspension compressor fails, the system can no longer adjust ride height, resulting in a rough ride and reduced ground clearance.
Another frequent issue is control arm bushing wear. The control arms play a crucial role in the vehicle’s handling, and worn-out bushings can lead to clunking noises, poor alignment, and excessive tire wear.
Many owners experience tie rod and ball joint wear, which causes loose steering and reduced stability at higher speeds.
Power steering failures are also a concern. Some G 65 AMG owners report heavy or inconsistent steering, often due to a failing power steering pump or leaking power steering fluid lines.
Given the weight and size of the G 65 AMG, any steering issue can significantly impact handling and safety.
Mercedes G-Class W463 G 65 AMG Electrical System Problems
The Mercedes G 65 AMG comes with a complex electrical system that controls various luxury and performance features.
However, many owners report persistent electrical issues, ranging from minor inconveniences to major system failures.
One of the most frequently reported problems is battery drain. Given the large number of electronic modules in the G 65 AMG, the vehicle can experience parasitic battery drain, leading to repeated dead battery incidents.
Many cases of battery drain are caused by faulty control modules, such as the SAM (Signal Acquisition Module), which controls various electrical functions. Malfunctioning door control modules, infotainment systems, or even keyless entry systems can also contribute to excessive battery drainage.
Another common issue is alternator failure. The V12 engine requires a high-output alternator to keep up with the demand of power-hungry systems.
When the alternator begins to fail, symptoms such as dim lights, warning messages, or sudden power loss may appear.
Many G 65 AMG owners also report malfunctions with the COMAND infotainment system. Problems include touchscreen freezing, navigation system errors, or complete system shutdowns.
Software updates can sometimes resolve these issues, but in many cases, replacing the infotainment module is the only solution.
Another frequently reported issue is central locking system failure. The actuators inside the doors tend to fail, preventing doors from locking or unlocking properly.
In extreme cases, the keyless entry system becomes unresponsive, requiring a manual override to access the vehicle.
Mercedes G-Class W463 G 65 AMG Brake System Failures
The G 65 AMG is a heavy and high-performance SUV, requiring a robust braking system. However, some owners report premature brake wear and malfunctions that can compromise safety.
One of the most common complaints is rapid brake pad and rotor wear. Due to the vehicle’s mass and power, the braking system is under immense stress. As a result, brake pads wear out quickly, and brake rotors may develop warping, causing vibrations and reduced braking efficiency. Many owners find themselves replacing brakes more frequently than expected.
Another major issue is brake fluid leaks, which typically occur due to failing brake lines or worn-out master cylinder seals. If the brake fluid level drops too low, braking performance is significantly reduced, posing a safety risk.
The G 65 AMG’s ABS (Anti-lock Braking System) is also prone to sensor failures. Malfunctioning wheel speed sensors can trigger warning lights on the dashboard and disable traction control or stability assistance. In some cases, the ABS module itself can fail, leading to inconsistent braking response and potential loss of control in emergency situations.
Mercedes G-Class W463 G 65 AMG Climate Control and HVAC Issues
The Mercedes G 65 AMG is designed for comfort, but its HVAC (Heating, Ventilation, and Air Conditioning) system is known to develop problems over time.
Many owners experience weak air conditioning performance, often due to a failing AC compressor or refrigerant leaks. Given the high temperatures inside the engine bay, AC components are exposed to extreme conditions, causing seals and hoses to degrade prematurely.
Another common issue is blend door actuator failure. These actuators control airflow direction and temperature distribution inside the cabin. When they fail, drivers may experience hot or cold air stuck on one side, or the inability to switch between vents.
The blower motor, responsible for circulating air, is also prone to failure. Many owners report intermittent fan operation, strange noises from the vents, or complete blower failure. Given that replacement requires dashboard disassembly, blower motor repairs can be costly.
Heated and ventilated seat malfunctions are another frequent complaint. Some G 65 AMG models experience burnt-out seat heating elements, leading to seats that no longer warm up properly. Ventilated seats, which use small fans to circulate air, often suffer from dust buildup or fan motor failure, reducing cooling effectiveness.
Rust and Corrosion Problems
Despite its boxy, rugged design, the G 65 AMG is not immune to rust and corrosion. While Mercedes has improved rust protection over the years, many owners still report rust appearing on critical body areas, particularly in regions with harsh winters or exposure to road salt.
One of the most commonly affected areas is the underbody and frame. The steel frame and suspension components tend to develop rust over time, especially if moisture and salt are not properly cleaned off. This can lead to structural weaknesses and increased repair costs.
Rust also appears frequently on door hinges, fender flares, and wheel arches. Given the square-shaped design of the G-Class, water tends to accumulate in certain areas, leading to paint bubbling and corrosion.
Another area prone to rust is the rear tailgate and spare tire mount. Water can seep behind the spare tire carrier, leading to hidden corrosion beneath the mounting points.
Owners can minimize rust issues by regularly washing the undercarriage, applying rust-proofing treatments, and checking for early signs of corrosion before they spread.
Mercedes G-Class W463 G 65 AMG Exhaust System Failures
The exhaust system on the G 65 AMG is subject to high temperatures and stress, leading to common failures over time.
One of the primary issues is cracked exhaust manifolds. Due to repeated heat cycles, the exhaust manifolds may develop cracks, leading to a ticking noise, reduced performance, and check engine lights.
Another frequent problem is catalytic converter failure. Given the V12 twin-turbo configuration, the G 65 AMG generates excessive heat, which can cause the catalytic converters to clog over time. This results in power loss, increased fuel consumption, and emissions failure.
Exhaust valve failures are another known issue. The G 65 AMG has an active exhaust system that changes sound profiles based on driving mode. Over time, the exhaust valve actuators may fail, leading to a stuck exhaust flap that alters performance and sound output.
Mercedes G-Class W463 G 65 AMG Conclusion
The Mercedes G-Class W463 G 65 AMG is an extraordinary SUV, blending extreme power with luxury. However, like any high-performance vehicle, it comes with its own set of challenges.
Owners frequently encounter issues related to:
Engine and turbocharger reliability
Cooling system failures and overheating risks
Transmission and drivetrain concerns
Suspension and steering problems
Electrical system malfunctions
Brake system wear and sensor failures
HVAC and climate control breakdowns
Rust and corrosion on key structural areas
Exhaust system deterioration and failures
Owning a G 65 AMG requires meticulous maintenance and proactive servicing to prevent major issues from escalating. While the V12 engine delivers unmatched performance, its high repair costs and complexity make it a vehicle that requires expert care.
If you need repairs, diagnostics, or professional servicing for your Mercedes G 65 AMG, visit us at:
European Auto Pro 253 Goodwood Road, Kings Park, 5034 South Australia
Our team of Mercedes-Benz specialists can help you address these common problems and keep your G 65 AMG running in peak condition for years to come.