The 2009 Mercedes-Benz GL450 is a robust luxury SUV built on the W164 platform, featuring a powerful 4.7L V8 engine (Engine Code 273.923.9). This sophisticated vehicle relies on precise engineering and high-quality lubricants to maintain performance, fuel efficiency, and longevity. Using the correct fluids is critical for protecting the internal components of this high-output engine, particularly given the stresses of highway driving, towing, or varying climate conditions. Proper lubrication ensures that heat is managed effectively, wear is minimized, and the vehicle’s complex systems—from the transmission to the braking system—operate smoothly for years to come.
Recommended AMSOIL Products
For the optimal maintenance of your 2009 GL450, AMSOIL offers a comprehensive range of synthetic lubricants designed to meet or exceed original equipment manufacturer specifications. These products provide superior protection against wear, sludge, and extreme temperatures.
- AMSOIL 5W-40 FS 100% Synthetic European Motor Oil – Specifically formulated for the unique demands of European gasoline, diesel, and hybrid vehicles, featuring a precise blend of synthetic base oils and premium additives.
- AMSOIL 0W-40 FS 100% Synthetic European Motor Oil – An excellent alternative viscosity option designed for European vehicles, providing exceptional protection in both extreme cold and high-temperature operations.
- AMSOIL Oil Filter – Delivers filtering efficiency of 99 percent at 20 microns, offering reduced restriction and greater capacity for contaminants to help reduce engine wear.
- AMSOIL Passenger Car & Light Truck Antifreeze & Coolant – A unique poly-organic acid (OAT) formulation that protects all cooling system metals, gaskets, and hoses for up to 150,000 miles or 5 years.
- AMSOIL Signature Series Fuel-Efficient 100% Synthetic Automatic Transmission Fluid – Withstands the rigors of heavy towing and elevated temperatures while remaining fluid in sub-zero conditions.
- AMSOIL DOT 3 and DOT 4 100% Synthetic Brake Fluid – Provides excellent ABS and traction-control responsiveness with a stable viscosity over a wide temperature range.
- AMSOIL 100% Synthetic Multi-Vehicle Power Steering Fluid – Reduces friction and helps seals remain soft to prevent leaks, offering strong anti-wear protection and excellent high-temperature stability.
Engine Oil and Filtration Specifications
Choosing the right motor oil viscosity is essential for the longevity of the 4.7L V8 engine found in the 2009 GL450. The engine requires a capacity of 9.5 quarts when performing a complete change with a filter replacement. For those operating in extremely cold climates or seeking the ultimate in protection, the AMSOIL 0W-40 FS formula is an ideal choice. This synthetic European motor oil ensures that the engine oil flows freely during cold starts while maintaining film strength under high-load conditions. Conversely, the AMSOIL 5W-40 FS oil provides excellent coverage and is highly rated for European vehicles that operate in a broader range of temperatures.
When changing the oil, filtration is just as critical as the oil itself. The engine requires an oil filter that can handle the high flow rates and fine particle capture necessary for a direct-injection or port-injection European V8. The AMSOIL Oil Filter is designed to provide filtering efficiency of 99 percent at 20 microns. This high level of filtration keeps engine parts lubricated and reduces the buildup of wear-causing contaminants. For those who prefer original equipment manufacturer (OEM)-branded replacement filters, WIX offers a premium option that exceeds OEM standards, as does the MANN-FILTERS filter. The air filter is also crucial for maintaining engine efficiency; the MANN-FILTERS Air Filter ensures that the engine breathes clean air, preventing debris from entering the combustion chamber.
Owners should note that on models equipped with an oil cooler, additional oil may be required if the cooler is drained during service. It is also recommended to allow five minutes after refilling the oil or turning off the engine before checking the oil level to ensure an accurate reading. The oil drain plug torque specification is 22 ft/lbs, ensuring a secure seal without damaging the threads.
Transmission and Transfer Case Care
The 2009 Mercedes-Benz GL450 utilizes a sophisticated automatic transmission system, specifically the 722.9 family. Proper maintenance of this transmission is vital for smooth shifting and extended component life. The fluid capacity for a total fill of the 7-speed transmission is 9.5 quarts. Whether your vehicle is equipped with or without the reduced-friction code (A89), the AMSOIL Signature Series Fuel-Efficient 100% Synthetic Automatic Transmission Fluid is recommended. This fluid is engineered to withstand the rigors of heavy towing, elevated temperatures, and challenging terrain, ensuring that the transmission remains fluid even in sub-zero conditions.
The AMSOIL OE Fuel-Efficient 100% Synthetic Automatic Transmission Fluid is also a suitable option for this vehicle, offering robust protection against wear. The transfer case, which distributes power to all wheels, requires regular attention as well. For the single-speed transfer case, the capacity is approximately 1.1 pints. The same AMSOIL Signature Series Fluid used for the transmission can be utilized here, providing a reliable synthetic lubricant that resists breakdown under load. The drain plug torque for the transfer case is specified at 18 ft/lbs. Additionally, the front differential requires approximately 2.3 pints of lubricant to function correctly.
Cooling System and Fluid Maintenance
Maintaining the cooling system is paramount for a high-compression V8 engine like the one in the GL450. The system holds 12.7 quarts of coolant. Using a high-quality antifreeze and coolant is essential to prevent corrosion, freezing, and overheating. The AMSOIL Passenger Car & Light Truck Antifreeze & Coolant is a 50/50 pre-mix formulation that provides protection up to 150,000 miles or 5 years. It is engineered to exceed OEM requirements and is compatible with all cooling system metals, gaskets, and hoses. For those who prefer to mix their own solution, the Concentrated AMSOIL Propylene Glycol Antifreeze and Engine Coolant offers protection up to 150,000 miles or 5 years in passenger cars and light trucks, with significantly higher mileage limits for heavy-duty applications.
The brake system on the GL450 operates with high precision and requires fluid that meets stringent standards. The vehicle uses DOT 4 fluid, and the AMSOIL DOT 3 and DOT 4 100% Synthetic Brake Fluid is an excellent upgrade. This synthetic brake fluid ensures stable viscosity across a wide temperature range, which is crucial for maintaining pedal feel and stopping power. It also provides excellent responsiveness for ABS and traction control systems. Furthermore, the power steering system benefits from the AMSOIL 100% Synthetic Multi-Vehicle Power Steering Fluid. This fluid helps seals remain soft to prevent leaks and resists heat degradation, ensuring quiet operation and long fluid life.
Seasonal Storage and Fuel System Health
For owners who store their vehicles during off-seasons or do not drive them frequently, protecting the internal components is vital. The AMSOIL Gasoline Stabilizer can keep fuel fresh for up to 12 months, protecting against varnish, gum buildup, and ethanol corrosion. When preparing the engine for long-term storage, the AMSOIL Engine Fogging Oil provides a highly effective rust preventive coating for internal components, protecting against moisture and corrosion during periods of inactivity.
Additionally, the fuel system can benefit from the AMSOIL P.i. Performance Improver Gasoline Additive. This additive helps restore fuel injectors to near 100% flow rate and can improve fuel economy while reducing the need for higher-octane fuels. It also helps prevent carbon buildup and controls pre-ignition knock, ensuring the engine runs smoothly and efficiently.
About the Vehicle: 2009 Mercedes-Benz GL450
The 2009 Mercedes-Benz GL450 represents a significant moment in the evolution of luxury SUVs, blending the rugged capability of an off-road vehicle with the refined comfort of a high-end sedan. As part of the W164 generation, the GL-Class was designed to compete in the premium segment, offering a spacious, versatile, and powerful driving experience. Under the hood sits the 4.7L V8 engine, which delivers substantial horsepower and torque, allowing the GL450 to tow trailers and haul cargo with ease while maintaining a smooth ride.
Owners of this vehicle appreciate its blend of on-road comfort and off-road prowess. The vehicle features advanced suspension technology that contributes to a confident driving character, whether navigating city streets or traversing rougher terrain. The interior is typically equipped with high-quality materials and modern amenities for its time, making it a favorite among families and luxury vehicle enthusiasts. The GL450’s reputation for durability and performance has made it a sought-after model, with many owners continuing to drive them well beyond their initial service intervals thanks to proper maintenance.
The 2009 model year is particularly noted for its robust engineering and the inclusion of sophisticated safety and handling technologies. As a four-door SUV with a full-size footprint, it offers ample room for passengers and cargo, making it an ideal choice for long road trips or daily commuting. The combination of a powerful V8 engine, four-wheel drive capability, and a well-appointed interior ensures that the GL450 remains a capable and desirable vehicle. Regular maintenance with high-quality synthetic fluids ensures that this powerful machine continues to perform as intended, providing peace of mind and reliability for years to come.