Ensuring the longevity and peak performance of your 2018 Mercedes-Benz G65 AMG requires more than just a routine oil change; it demands fluids engineered specifically for the extreme demands of its 6.0L twin-turbo V12 engine. The AMG’s powertrain operates under immense stress, generating significant heat and friction that standard mineral oils cannot manage effectively. By utilizing high-quality synthetic motor oils, you protect critical internal components from wear, maintain optimal viscosity in extreme temperatures, and support the vehicle’s extended service intervals.
Whether you are navigating city traffic with the added stress of a turbocharged engine or tackling a weekend drive through challenging terrain, the right fluids are your first line of defense. This guide outlines the precise lubrication specifications, capacities, and product recommendations tailored for the G65 AMG’s unique engineering requirements, ensuring your luxury SUV continues to deliver its renowned power and smoothness.
Recommended AMSOIL Products
- AMSOIL 5W-40 FS 100% Synthetic European Motor Oil – Engineered with a precise blend of synthetic base oils and premium additives to meet the specific requirements of European vehicles, this oil provides exceptional protection for turbocharged engines. It is ideal for all temperatures and offers superior cleanliness.
- AMSOIL 0W-40 FS 100% Synthetic European Motor Oil – This ultra-low viscosity option flows instantly to critical engine parts during cold starts, reducing wear and tear. Like its 5W-40 counterpart, it features a specialized European formula designed for gasoline, diesel, and hybrid vehicles, ensuring comprehensive protection.
- AMSOIL Signature Series Fuel-Efficient 100% Synthetic Automatic Transmission Fluid – Withstands the rigors of heavy towing, elevated temperatures, and challenging terrain while maintaining fluidity in sub-zero conditions. This fluid provides reserve protection during the high-stress operation typical of the G65 AMG’s 7-speed automatic transmission.
- AMSOIL OE Fuel-Efficient 100% Synthetic Automatic Transmission Fluid – A cost-effective option that still delivers robust protection against wear for the automatic transmission. It is suitable for both configurations with and without the reduced-friction code, ensuring reliable performance under various operating conditions.
- AMSOIL Passenger Car & Light Truck Antifreeze & Coolant – A unique poly-organic acid (OAT) formulation that protects all cooling system metals, gaskets, and hoses. This 50/50 pre-mix provides protection up to 150,000 miles or 5 years, exceeding original equipment manufacturer requirements for your G65’s cooling system.
- AMSOIL Propylene Glycol Antifreeze and Engine Coolant – A concentrated coolant that requires mixing with distilled water, offering up to 150,000 miles of protection in passenger cars. It greatly surpasses standards for metallic corrosion and erosion, making it an excellent choice for long-term cooling system health.
- AMSOIL DOT 3 and DOT 4 100% Synthetic Brake Fluid – Designed to provide excellent ABS and traction-control responsiveness with stable viscosity over a wide temperature range. This fluid meets the strict requirements of MB Sheet 331.0, ensuring safe and precise braking performance.
- AMSOIL 100% Synthetic Multi-Vehicle Power Steering Fluid – Reduces friction and helps seals remain soft to prevent leaks, resisting heat for extended fluid life. Formulated for quiet operation and high-temperature performance, it ensures smooth steering control in your G65 AMG.
Engine Oil Specifications and Maintenance
The heart of your 2018 G65 AMG is the 6.0L V12 engine, designated by the internal code 279.98 H Turbo. This powerplant generates immense horsepower and torque, relying heavily on the quality of its lubrication. For the crankcase, the manufacturer recommends oil grades that can handle extreme thermal loads while maintaining proper flow characteristics. The total capacity for this engine, including the oil filter, is 11.1 quarts. After refilling the system, it is crucial to check the oil level to ensure it is within the safe operating range.
When changing the oil, the drain plug must be torqued to exactly 22 ft/lbs to prevent leaks or damage to the aluminum oil pan. Additionally, the drain plug seal should always be replaced during service to maintain a perfect seal. AMSOIL offers two premium motor oils for this application: the 5W-40 FS and the 0W-40 FS. Both are 100% synthetic European formulas designed for the unique demands of gasoline, diesel, and hybrid European vehicles. They feature a precise blend of synthetic base oils and premium additives that provide superior shear stability, thermal resistance, and engine cleanliness compared to conventional oils.
Choosing between 5W-40 and 0W-40 depends on your climate and driving habits. The 0W-40 offers enhanced cold-start protection and immediate oil flow, which is beneficial for short trips or very cold climates. The 5W-40 provides excellent stability for high-temperature operation and sustained driving. Both oils meet the rigorous standards required by Mercedes-Benz AMG vehicles, ensuring that the complex valvetrain and turbocharger bearings are fully lubricated under all conditions.
Transmission and Drivetrain Fluids
The transmission in the 2018 G65 AMG is a 7-speed automatic unit with the designation 722.9. The specific fluid required can vary based on the presence of a reduced-friction code on the data card. For transmissions equipped with code A89 (Reduced-Friction), as well as those without this code, a total fill capacity of 9.5 quarts is recommended for the 7-speed unit. Maintaining the correct fluid is vital for shifting performance and longevity.
AMSOIL Signature Series Fuel-Efficient 100% Synthetic Automatic Transmission Fluid is a top recommendation for this application. It is designed to withstand the rigors of heavy towing, elevated temperatures, and challenging terrain. This fluid remains fluid even in sub-zero temperatures, providing reserve protection during heavy use and abuse. For those seeking a high-performance yet cost-effective option, the OE Fuel-Efficient 100% Synthetic Automatic Transmission Fluid also offers excellent protection against wear for the automatic transmission, suitable for the specific 722.9 unit configurations.
For the transfer case and differentials, while specific fluid recommendations were not listed in the primary fitment data, maintaining proper lubrication is essential for the four-wheel-drive system. The front differential requires 3 pints, and the rear differential requires 3.8 pints. Keeping these components lubricated with high-quality synthetic gear oils or appropriate transfer case lubricants ensures smooth power distribution and reduces wear on the gear sets.
Cooling System and Fluids
The cooling system capacity for the 2018 Mercedes-Benz G65 AMG is 14.8 quarts. Given the high-output nature of the V12 engine, maintaining optimal cooling temperature is critical to prevent overheating and component warping. AMSOIL offers two antifreeze options for this vehicle: a 50/50 pre-mix formulation and a concentrated propylene glycol option.
The Passenger Car & Light Truck Antifreeze & Coolant is a phosphate-, nitrate-, nitrite-, silicate-, borate-, and amine-free formulation that protects all cooling system metals, gaskets, and hoses. It is compatible with all other antifreeze and coolant colors, offering protection for up to 150,000 miles or 5 years. For those who prefer to mix their own coolant, the Propylene Glycol Antifreeze and Engine Coolant provides up to 150,000 miles of protection in passenger cars and light trucks, with excellent resistance to corrosion and erosion. This concentrated option allows for precise mixing to match local climate conditions.
Brake and Steering Fluids
Brake fluid performance is paramount for a vehicle of this caliber. For the G65 AMG, AMSOIL DOT 3 and DOT 4 100% Synthetic Brake Fluid is recommended. It is specifically approved for use with MB specifications (MB Sheet 331.0) and provides excellent ABS and traction-control responsiveness. The fluid maintains stable viscosity over a wide temperature range, ensuring consistent pedal feel and safe stopping power in both freezing and scorching conditions.
Power steering fluid is another critical component often overlooked. The AMSOIL 100% Synthetic Multi-Vehicle Power Steering Fluid is designed to reduce friction, help seals remain soft to prevent leaks, and resist heat for long fluid life. It offers strong anti-wear protection and excellent high-temperature and low-temperature performance, ensuring the power steering system operates quietly and efficiently.
Seasonal Storage and Fuel System Care
When the vehicle is not in use, proper storage preparation can prevent costly damage. AMSOIL Gasoline Stabilizer helps keep fuel fresh for up to 12 months, protecting against varnish and gum buildup while fighting ethanol corrosion. For long-term storage, AMSOIL Engine Fogging Oil is a highly effective rust preventive designed to protect internal engine components during long periods of inactivity.
For everyday driving, maintaining a clean fuel system is essential for maximizing the performance of the turbocharged engine. AMSOIL P.i. Performance Improver Gasoline Additive can restore up to 14% horsepower and clean GDI fuel injectors to 100% flow rate after just one tank of fuel. It improves fuel economy, reduces the need for higher-octane fuel, and helps prevent carbon rap and pre-ignition knock.
About the Vehicle: The Mercedes-Benz G65 AMG
The 2018 Mercedes-Benz G65 AMG represents the pinnacle of luxury off-roading, combining rugged utility with opulent comfort and immense performance. As a member of the iconic G-Class family, often referred to as the “G-Wagon,” this model has a storied history dating back to the 1970s. Originally designed as a utilitarian military vehicle, the G-Class evolved into a symbol of status and capability, and the G65 AMG takes this legacy to new heights with its exclusive AMG powertrain.
The defining feature of the G65 AMG is its 6.0-liter twin-turbocharged V12 engine. This massive internal combustion engine produces an astounding 621 horsepower and a mind-bending 738 lb-ft of torque. In 2018, this made it one of the most powerful production vehicles on the road, delivering a level of acceleration that belies its substantial size and weight. The driving character is unique; it offers a blend of the raw, muscular thrust expected from a V12 and the plush, quiet ride typical of a high-end S-Class, all while maintaining the off-road prowess of the G-Class platform.
Owners of the G65 AMG value this vehicle for its unparalleled presence and versatility. It commands attention wherever it goes, serving as a daily driver for those who need to traverse difficult terrain or as a grand tourer for those seeking ultimate comfort. The G65 is positioned as a flagship vehicle for the AMG brand, sitting at the top of the G-Class lineup. Its interior is a sanctuary of leather, wood, and aluminum, designed to isolate occupants from the outside world while providing a commanding view of the road ahead. The G65 is a statement piece that balances the needs of a performance enthusiast with the demands of a luxury lifestyle.
However, maintaining such a complex and powerful machine presents specific challenges. One common issue with the G65 AMG is the potential for carbon buildup on the intake valves, especially in Direct Injection (GDI) engines. Over time, this buildup can lead to rough idling, reduced fuel efficiency, and a loss of power. AMSOIL P.i. Fuel Additive is an effective solution for this, helping to clean injectors and reduce carbon deposits to restore performance.
Another prevalent problem in high-mileage G65s is the degradation of engine seals due to heat. The high operating temperatures of the V12 engine can cause rubber seals to harden and shrink, leading to oil leaks. AMSOIL’s synthetic motor oils and seal conditioners are formulated to keep seals soft and pliable, preventing leaks and extending the life of the engine components. Additionally, the G65’s complex 4-wheel-drive system and heavy components can put stress on suspension bushings and metal surfaces, leading to corrosion or wear in harsh environments. AMSOIL’s MP Metal Protector and Synthetic Multi-Purpose Grease products provide a durable barrier against rust and corrosion, protecting the chassis and moving parts from the elements.
Finally, the G65’s heavy weight and high torque can strain the cooling system during extreme driving conditions, such as towing or aggressive acceleration in hot weather. Ensuring the cooling system is flushed with high-quality antifreeze and coolant is critical to prevent overheating. The extended service intervals of AMSOIL coolants mean less frequent maintenance while providing superior protection against the thermal stresses of the G65’s powerful engine. By addressing these common issues with the right lubricants and additives, owners can preserve the performance and value of their G65 AMG for years to come.
Maintaining a 2018 Mercedes-Benz G65 AMG requires a commitment to using high-performance fluids that can keep up with the vehicle’s extreme capabilities. From the moment the engine starts until the final stop, every component benefits from the advanced protection offered by AMSOIL synthetic lubricants. Whether you are changing the oil, refreshing the coolant, or conditioning the brake fluid, using the recommended products ensures that your G65 continues to deliver the power and luxury you expect. For further assistance in selecting the right fluids or learning more about AMSOIL’s products, visiting amsoil.com is the best way to ensure your vehicle receives the care it deserves.