The 2009 Mercedes-Benz ML320 with the 3.0L 6-cylinder turbo-diesel engine (Engine Code 642.820 F) is a robust vehicle that demands precision maintenance to preserve its performance and longevity. European diesel engines, in particular, operate under high stress and temperatures, making the use of high-quality synthetic lubricants essential. Proper fluid selection ensures optimal viscosity control, superior wear protection, and extended service intervals, allowing this luxury SUV to deliver the smooth, reliable driving experience it was designed for.
Recommended AMSOIL Products
- AMSOIL 0W-30 MS 100% Synthetic European Motor Oil – A unique formulation designed specifically for the precise demands of European gasoline, diesel, and hybrid engines, offering superior protection against high temperatures and sludge.
- MANN-FILTERS Oil Filter (HU821X) – Features premium filtration media that outperforms standard OEM filters to trap contaminants and ensure clean oil circulation throughout the engine.
- AMSOIL Signature Series Fuel-Efficient 100% Synthetic Automatic Transmission Fluid – Provides exceptional protection for the 722.9 transmission, reducing heat and friction while extending fluid life even under severe driving conditions.
- AMSOIL DOT 3 and DOT 4 100% Synthetic Brake Fluid – Delivers excellent ABS responsiveness and stability at extreme temperatures, ensuring safe and consistent braking performance.
- AMSOIL 100% Synthetic Multi-Vehicle Power Steering Fluid – Helps maintain seal flexibility, reduces friction, and resists heat for longer fluid life in both belt-driven and electro-hydraulic systems.
- AMSOIL Passenger Car & Light Truck Antifreeze & Coolant – A 50/50 pre-mixed formulation that protects cooling system metals, gaskets, and hoses for up to 150,000 miles or 5 years.
Essential Engine Oil for the ML320 Diesel
The heart of your 2009 ML320 is the 3.0L turbodiesel engine, a sophisticated unit that requires oil capable of handling high loads and exhaust gas recirculation systems. Standard conventional oils simply cannot provide the necessary protection for this engine over the long term. The recommended viscosity is 0W-30 or 5W-30, suitable for all operating temperatures. The total oil capacity for a standard change, including the filter replacement, is 9.0 quarts. If your vehicle is equipped with an external oil cooler, additional oil may be required when the cooler is drained, so checking the dipstick after refill is a critical step. Allow the engine to sit for five minutes after turning it off or refilling before checking the oil level to ensure an accurate reading.
For this application, the AMSOIL 0W-30 MS 100% Synthetic European Motor Oil is the ideal choice. It features a precise blend of synthetic base oils and premium additives designed specifically for the unique demands of European diesel vehicles. This oil helps reduce deposit formation, ensures rapid flow during cold starts, and maintains film strength under the high thermal stress typical of turbocharged diesel engines. The torque specification for the oil drain plug is 22 ft/lbs, which should be adhered to during service to prevent threading issues or leaks. Pairing this premium oil with a high-quality MANN-FILTERS oil filter ensures that contaminants are effectively trapped, keeping the engine interior clean and extending the life of critical components.
Transmission and Drivetrain Maintenance
The ML320 is equipped with a 7-speed automatic transmission (Model 722.9), which requires a fluid that can withstand the rigors of shifting under load while providing smooth operation. The transmission fluid capacity varies slightly depending on the specific configuration and the data card codes (such as A89 for reduced friction), but the total fill for the 722.9 transmission is approximately 9.5 quarts. Using a fluid designed for these modern automatic transmissions is crucial to maintain shift quality and protect internal gears and clutches from wear.
AMSOIL offers two distinct options for this transmission. The Signature Series Fuel-Efficient 100% Synthetic Automatic Transmission Fluid is engineered to withstand heavy towing, elevated temperatures, and challenging terrain, while remaining fluid in sub-zero conditions. Alternatively, the OE Fuel-Efficient 100% Synthetic Automatic Transmission Fluid provides robust protection against wear and is a cost-effective solution that still meets the high standards required by Mercedes-Benz. Both fluids help reduce friction, which can improve fuel economy, and are designed to last well beyond conventional drain intervals, making them a smart investment for owners looking to maximize the lifespan of their drivetrain.
Cooling System and Fluids
Proper cooling system maintenance is vital for the longevity of the diesel engine. The cooling capacity for the 2009 ML320 is 10 quarts. For long-term protection, AMSOIL Passenger Car & Light Truck Antifreeze & Coolant offers a convenient 50/50 ethylene glycol pre-mix formulation that requires no mixing. It is phosphate-, nitrate-, nitrite-, silicate-, borate-, and amine-free, making it safe for all cooling system metals and compatible with other antifreeze colors. For those who prefer a concentrated solution, the AMSOIL Propylene Glycol Antifreeze and Engine Coolant offers extended protection up to 150,000 miles or 5 years in passenger cars and light trucks.
Brake and Steering Systems
Safety is paramount in a vehicle of this stature. The braking system on the ML320 requires a fluid that meets strict Mercedes-Benz specifications, such as DOT 4. AMSOIL DOT 3 and DOT 4 100% Synthetic Brake Fluid exceeds these requirements, offering excellent responsiveness for ABS and traction control systems. It provides a stable viscosity over a wide temperature range, ensuring that pedal feel remains consistent whether you are driving on a steep mountain pass or in stop-and-go city traffic.
Similarly, the power steering system benefits from a synthetic fluid that resists heat breakdown. Whether your ML320 has a belt-driven pump or an electro-hydraulic system, the AMSOIL 100% Synthetic Multi-Vehicle Power Steering Fluid is formulated to reduce friction, keep seals soft to prevent leaks, and operate quietly. It offers strong anti-wear protection and excellent high- and low-temperature performance, ensuring precise steering control in all weather conditions.
Diesel Fuel and Additional Protection
As a diesel vehicle, the ML320 can benefit from fuel additives that improve combustion and protect the fuel system. AMSOIL offers a range of diesel fuel additives, including Diesel Injector Clean to improve lubricity and detergency, and Diesel Cetane Boost to increase horsepower and fuel economy. For colder climates, the Diesel Cold Flow Fuel Additive lowers the cold filter-plugging point, preventing gelling during winter storage or operation. For comprehensive protection, the AMSOIL Diesel Injector Clean + Cetane Boost Fuel Additive combines these benefits, while the AMSOIL Diesel 4-IN-1 Fuel Additive offers detergency, lubricity, cold flow, and cetane boost in one package. Additionally, WIX Fuel Filters and MANN-FILTERS Fuel Filters ensure clean fuel delivery. For maintenance outside the fuel system, consider AMSOIL Synthetic Multi-Purpose Grease for bearings, AMSOIL Heavy-Duty Metal Protector for undercarriage care, or the AMSOIL Miracle Wash Waterless Wash and Wax Spray for exterior maintenance.
About the 2009 Mercedes-Benz ML320
The 2009 Mercedes-Benz ML320 represents the second generation of the M-Class, a vehicle that successfully bridged the gap between luxury sedan comfort and rugged off-road capability. Built on a dedicated SUV platform, the ML320 was renowned for its sophisticated engineering and high level of refinement. The 3.0L OM642 turbodiesel engine, powering this specific model, is a highly respected unit known for its torque delivery and relative reliability when properly maintained. This engine produces substantial low-end torque, making the ML320 an engaging vehicle to drive, capable of towing and hauling with ease.
Owners of this vehicle often appreciate its balanced handling and premium interior appointments, which were considered top-tier for the luxury SUV segment at the time. The ML320 offered a versatile driving character, handling well on paved roads while maintaining the off-road prowess expected of a Mercedes-Benz. It sits on a robust chassis that supports all-wheel drive configurations, providing confidence in various weather conditions. As a product of German engineering, the ML320 embodies a philosophy of durability and performance, designed to serve as a reliable daily driver as well as a weekend adventure vehicle. Maintaining this vehicle with high-quality fluids ensures that its legacy of performance and comfort continues for years to come.