Ensuring the 2008 Mercedes-Benz GL550 receives the proper lubrication is essential for maintaining the longevity and performance of its robust 5.5L V8 engine. This vehicle features a complex engine design with specific cooling and filtration needs that standard commercial oils may not fully address. Using high-quality synthetic fluids designed for European vehicles helps mitigate the effects of extreme temperatures, reduces wear during stop-and-go traffic or towing, and ensures the transmission and differential systems operate within optimal parameters. Below is a comprehensive guide to the recommended fluids and filters for this specific model.
Recommended AMSOIL Products
- AMSOIL 5W-40 FS 100% Synthetic European Motor Oil – Specifically formulated with a European additive package to meet the strict requirements of the GL550 engine, providing superior protection against sludge and high-temperature breakdown.
- AMSOIL 0W-40 FS 100% Synthetic European Motor Oil – An excellent alternative viscosity option for this engine, offering exceptional cold-start protection while maintaining optimal film strength in hot operating conditions.
- AMSOIL Oil Filter – Delivers 99% filtration efficiency at 20 microns, allowing for lower restriction and better lubrication of engine parts compared to standard OEM filters.
- WIX Oil Filter – A premium aftermarket option featuring high-efficiency media that outperforms original equipment manufacturer-branded filters in trapping wear-causing contaminants.
- AMSOIL Passenger Car & Light Truck Antifreeze & Coolant – A pre-mixed formulation that protects cooling system metals, gaskets, and hoses for up to 150,000 miles or five years, compatible with all coolant colors.
- AMSOIL Propylene Glycol Antifreeze and Engine Coolant – A concentrated, high-efficiency coolant that greatly surpasses industry standards for corrosion and erosion protection in passenger cars and light trucks.
- AMSOIL Signature Series Fuel-Efficient 100% Synthetic Automatic Transmission Fluid – Designed to withstand heavy towing and elevated temperatures, ensuring the 7-speed 722.9 transmission remains fluid and responsive in sub-zero conditions.
- AMSOIL OE Fuel-Efficient 100% Synthetic Automatic Transmission Fluid – Provides essential wear protection and thermal stability for the GL550’s automatic transmission system.
The 5.5L V8 engine in the 2008 GL550 is a high-performance powerhouse that demands precise lubrication. The engine oil capacity for a complete change with a filter is 9.5 quarts. It is critical to note that after refilling, you must check the oil level to ensure accuracy. This engine benefits significantly from the synthetic formulation found in the AMSOIL 5W-40 FS and 0W-40 FS oils, which offer a precise blend of base oils and premium additives tailored for European gasoline, diesel, and hybrid vehicles. These fluids provide a level of cleanliness and wear protection that extends the service life of critical engine components.
Cooling System and Thermal Management
Adequate cooling is paramount for the longevity of the GL550. The cooling system holds a capacity of 12.7 quarts. For this volume, AMSOIL offers two distinct solutions. The AMSOIL Passenger Car & Light Truck Antifreeze & Coolant is an ethylene glycol 50/50 pre-mix that requires no mixing and offers protection for 150,000 miles or five years. It is phosphate, nitrate, nitrite, silicate, borate, and amine-free, ensuring compatibility with all other antifreeze colors. Alternatively, the AMSOIL Propylene Glycol Antifreeze and Engine Coolant is a concentrated formula that requires mixing with distilled water. This option offers extended protection up to 150,000 miles or five years and is ideal for owners seeking maximum corrosion resistance and high-temperature stability. Both options protect all cooling system metals, gaskets, and hoses from the harsh chemical breakdown that can occur over time.
Transmission and Drivetrain Fluids
The 2008 GL550 is equipped with a 7-speed automatic transmission (722.9), which comes in two variations: one with code SL057 (without reduced friction) and one with code SL058 (with reduced friction code A89). Regardless of the specific data card code, the total fill capacity for the transmission is 9.5 quarts. To handle the rigors of a full-size luxury SUV, the AMSOIL Signature Series Fuel-Efficient 100% Synthetic Automatic Transmission Fluid is highly recommended. It is engineered to remain fluid in sub-zero temperatures while providing reserve protection during heavy towing or challenging terrain. The AMSOIL OE Fuel-Efficient 100% Synthetic Automatic Transmission Fluid is also a viable option, offering reliable wear protection for daily driving conditions. Maintaining these fluids is crucial to prevent sludge buildup and temperature-related transmission issues.
Differential and Transfer Case Lubrication
The GL550’s four-wheel-drive system requires specific attention to its transfer case. Depending on the vehicle configuration, specifically whether it has code 430 or not, the transfer case capacity varies significantly. For transfer cases with code 430, the capacity is 3.2 pints, while those without code 430 require 1.1 pints. The AMSOIL Signature Series Fuel-Efficient 100% Synthetic Automatic Transmission Fluid can also be utilized for transfer case lubrication in these applications, ensuring the gears remain protected against wear and thermal degradation. The AMSOIL OE Fuel-Efficient 100% Synthetic Automatic Transmission Fluid provides another viable option for these applications, ensuring gears remain protected against wear and thermal degradation. Proper lubrication here ensures smooth power distribution and prevents binding in the drivetrain components.
Fuel System and Maintenance
To maintain peak performance, fuel system integrity is equally important. The AMSOIL P.i. Performance Improver Gasoline Additive is recommended to restore fuel injectors, particularly for GDI systems, and can restore up to 14% horsepower in certain conditions. For seasonal storage, AMSOIL Gasoline Stabilizer keeps fuel fresh for up to 12 months, fighting ethanol corrosion and varnish buildup. Additionally, AMSOIL Engine Fogging Oil provides a rust preventative layer for internal engine components during long periods of inactivity, making it ideal for owners who store their vehicles during winter months. For general cleaning, the AMSOIL Upper Cylinder Lubricant lubricates the fuel system and upper cylinders, protecting against carbon buildup.
Regular maintenance with these specialized fluids and filters ensures that the 2008 Mercedes-Benz GL550 operates at its best. Whether you are facing extreme cold, towing heavy loads, or simply want to extend the time between service intervals, the comprehensive protection offered by AMSOIL synthetic lubricants makes a significant difference in the vehicle’s reliability and performance.
About the Vehicle
The 2008 Mercedes-Benz GL550 represents a significant step in the brand’s evolution of luxury sport utility vehicles. Positioned as a high-performance 4×4, the GL-Class (now the GLS) combines the rugged capabilities of an off-road vehicle with the opulence and refinement expected of a premium Mercedes-Benz. The 2008 model year features the 5.5L M273 V8 engine, which delivers substantial power suitable for both highway cruising and light off-road excursions. Known for its commanding road presence and smooth ride quality, the GL550 was designed to carry up to seven passengers comfortably while maintaining a level of driving dynamics that rivals smaller sedans.
Owners of the GL550 often appreciate its versatility, which allows for easy navigation of city streets without sacrificing the capability to tackle challenging terrains when needed. The vehicle’s architecture, based on a robust ladder frame, provides durability and strength, making it a reliable choice for families who require a spacious interior and powerful engine. The integration of advanced safety systems and comfort features typical of the Mercedes-Benz lineup during this era ensures that the driving experience is both secure and luxurious. As a full-size luxury SUV, the GL550 holds a reputation for being a versatile tool for everyday life while offering the prestige and engineering excellence associated with the German manufacturer. Its design focuses on balancing performance, utility, and comfort, making it a favored choice for drivers who demand the best from their automotive equipment.