The 2008 Mercedes-Benz S550 is a sophisticated luxury sedan powered by a 5.5-liter V8 engine with the specific engine code 273.961 4. This German engineering masterpiece demands precision lubrication to maintain its smooth operation, handling dynamics, and longevity. Regular maintenance using high-quality fluids is essential to protect the engine’s internal components from wear, especially given the high-performance nature of this vehicle. Proper fluid selection also ensures optimal performance in varying climates and extends the service intervals for critical systems like the transmission and cooling.
Recommended AMSOIL Products
- AMSOIL 5W-40 FS 100% Synthetic European Motor Oil – Specifically designed for the unique demands of gasoline, diesel, and hybrid European vehicles with precise blends of synthetic base oils and premium additives.
- AMSOIL 0W-40 FS 100% Synthetic European Motor Oil – Provides exceptional protection in extreme temperatures while meeting the strict specifications required by modern Mercedes-Benz engines.
- AMSOIL Oil Filter – Offers a 99 percent filtering efficiency at 20 microns, reducing engine wear and offering extended service life compared to standard filters.
- WIX Oil Filter – Features premium media that provides improvements over original equipment manufacturer-branded filters for superior contaminant removal.
- MANN-FILTERS Oil Filter – A high-quality alternative compatible with the vehicle’s requirements, ensuring clean oil circulation through the engine.
- MANN-FILTERS Air Filters – Provides premium air filtration to ensure the engine breathes clean air, maximizing combustion efficiency and power output.
- AMSOIL Passenger Car & Light Truck Antifreeze & Coolant – A unique phosphate-free formulation that protects all cooling system metals, gaskets, and hoses for up to 150,000 miles or 5 years.
- AMSOIL Propylene Glycol Antifreeze and Engine Coolant – A concentrated option that surpasses industry standards for corrosion and erosion protection in passenger cars and light trucks.
- AMSOIL Signature Series Fuel-Efficient 100% Synthetic Automatic Transmission Fluid – Withstands heavy towing and elevated temperatures while remaining fluid in sub-zero conditions to protect the transmission.
- AMSOIL OE Fuel-Efficient 100% Synthetic Automatic Transmission Fluid – Provides essential wear protection and meets OEM standards for automatic transmissions.
- AMSOIL DOT 3 and DOT 4 100% Synthetic Brake Fluid – Delivers excellent ABS and traction-control responsiveness with stable viscosity across a wide temperature range.
- AMSOIL 100% Synthetic Multi-Vehicle Power Steering Fluid – Reduces friction and helps seals remain soft to prevent leaks, ensuring quiet and reliable steering operation.
Engine Oil and Filter Specifications
For the 2008 Mercedes-Benz S550, proper engine lubrication is the foundation of reliable performance. The 5.5L V8 engine (Engine Code 273.961 4) requires a high-quality synthetic oil that can handle the stresses of high RPMs and varying operating conditions. The recommended oil capacity is 9.0 quarts when changing the oil filter. On models equipped with an oil cooler, additional oil may be necessary if the cooler is drained during service. It is crucial to allow at least five minutes after refilling or turning the engine off before checking the oil level to ensure an accurate reading. The oil drain plug should be torqued to 22 ft/lbs to prevent leaks or damage to the pan threads.
AMSOIL offers two primary viscosity options suitable for this European V8: the AMSOIL 5W-40 FS 100% Synthetic European Motor Oil and the AMSOIL 0W-40 FS 100% Synthetic European Motor Oil. Both formulations are designed with a precise blend of synthetic base oils and premium additives to meet the exacting requirements of Mercedes-Benz powertrains. The 0W-40 grade provides superior cold-start protection, making it ideal for extreme winter temperatures, while the 5W-40 offers a robust protection layer for a wide range of climates, performing well in temperatures above -25°C. Regardless of the viscosity chosen, these oils provide a protective barrier that reduces friction and minimizes wear on critical engine components.
Filtration is equally critical to maintaining engine health. The AMSOIL Oil Filter (Part Code: EA15K39-EA) is engineered to provide filtering efficiency of 99 percent at 20 microns. This high level of filtration allows for lower restriction, keeping engine parts properly lubricated while holding greater capacity for small, wear-causing contaminants than many competing filters. For owners who prefer alternative branded filters, the WIX Oil Filter (Part Code: 57078-EA) and MANN-FILTERS Oil Filter (Part Code: HU7185X-EA) also offer premium media improvements over standard OEM-branded units, ensuring contaminants are effectively removed from the circulation loop.
Transmission, Cooling, and Brake Systems
The automatic transmission in the 2008 S550 is a 7-speed unit (722.9 series) that benefits significantly from synthetic fluid. Depending on whether the vehicle has the Reduced-Friction code (A89) or not, the total fill capacity is 10.4 quarts. Using a high-performance synthetic transmission fluid is vital for protecting the transmission from sludge, wear, and temperature-related issues, ensuring smooth shifts and extended fluid life. The AMSOIL Signature Series Fuel-Efficient 100% Synthetic Automatic Transmission Fluid (Part Code: ATLPK-EA) is designed to withstand the rigors of heavy towing, elevated temperatures, and challenging terrain while remaining fluid in sub-zero conditions. The AMSOIL OE Fuel-Efficient 100% Synthetic Automatic Transmission Fluid (Part Code: OTLQT-EA) offers a robust option that protects against wear and meets original equipment manufacturer specifications.
Cooling system maintenance is essential to prevent overheating and corrosion. The 2008 S550 requires 12.2 quarts of AMSOIL Passenger Car & Light Truck Antifreeze & Coolant with rear air conditioning and 13.8 quarts without rear air conditioning. This Antifreeze & Coolant (Part Code: ANTPC1G-EA) is a 50/50 pre-mix formulation that protects all cooling system metals, gaskets, and hoses. It is phosphate-free and compatible with all other antifreeze colors. For those who prefer a concentrated fluid, AMSOIL Propylene Glycol Antifreeze and Engine Coolant (Part Code: ANT1G-EA) offers superior corrosion protection and can extend service life up to 150,000 miles or 5 years.
AMSOIL DOT 3 and DOT 4 100% Synthetic Brake Fluid integrity is crucial for the safety and performance of the S550. The vehicle recommends DOT 4 Plus or products approved on MB Sheet 331.0. This Brake Fluid (Part Code: BFLVCN-EA) provides excellent ABS and traction-control responsiveness with a stable viscosity over a wide temperature range. Additionally, the power steering system benefits from AMSOIL 100% Synthetic Multi-Vehicle Power Steering Fluid (Part Code: PSFCN-EA), which reduces friction, prevents leaks by keeping seals soft, and resists heat for long fluid life.
About the Vehicle
The 2008 Mercedes-Benz S550 represents the pinnacle of luxury and engineering from the W221 generation, which was produced from 2005 to 2013. This full-size sedan is renowned for its blend of opulent comfort and dynamic driving capability. Powered by the M273 5.5-liter V8 engine, the S550 delivers a smooth and powerful driving experience that is characteristic of German luxury performance. The engine, with its code 273.961 4, is designed to provide strong acceleration while maintaining a refined and quiet cabin environment.
As a flagship model, the S-Class sets the tone for the Mercedes-Benz brand, often serving as the testing ground for new technologies that eventually trickle down to other models. Owners of the 2008 S550 appreciate its advanced safety features, luxurious interior appointments, and sophisticated suspension systems that adapt to road conditions. The vehicle’s reputation for reliability and durability is well-established, provided that it receives consistent and high-quality maintenance. Using the correct lubricants and filters is not just about adhering to a schedule; it is about preserving the driving dynamics and comfort that made the S550 a benchmark in the luxury sedan segment. Whether used for daily commuting or long-distance travel, the S550 remains a highly regarded vehicle for those who value performance, comfort, and engineering excellence.