The 2007 Mercedes-Benz CL550 is a sophisticated grand tourer featuring a 5.5-liter V8 engine (Engine Code 273.961 2) built on the W216 platform. Owners of this high-performance luxury coupe demand fluids that can withstand the stresses of a powerful naturally aspirated engine while maintaining the smoothness and reliability expected from German engineering. Proper lubrication is not merely about following an interval; it is about preserving the precise tolerances of the 7-speed automatic transmission and ensuring the cooling system operates efficiently under the load of high-speed highway driving or spirited cornering.
Recommended AMSOIL Products
For this vehicle, the engine requires a specialized European formula to handle the tight clearances and high thermal loads. The engine oil capacity for a complete service, including the filter, is 9.0 quarts. Below are the essential AMSOIL products designed to maximize the lifespan and performance of your CL550.
- AMSOIL 5W-40 FS 100% Synthetic European Motor Oil – A European-formulated synthetic designed for the unique demands of Mercedes-Benz engines, offering superior wear protection and thermal stability.
- AMSOIL 0W-40 FS 100% Synthetic European Motor Oil – Provides excellent flow in extreme cold temperatures while maintaining a robust protective film at high operating temperatures.
- AMSOIL Oil Filter – Engineered to capture 99% of contaminants down to 20 microns, ensuring clean oil circulates through the complex V8 engine.
- WIX Oil Filter – A premium alternative with superior media that outperforms original equipment filters in capturing wear-causing contaminants.
- AMSOIL Signature Series Fuel-Efficient 100% Synthetic Automatic Transmission Fluid – Specifically formulated for the 722.9 transmission, providing superior protection against heavy towing, elevated temperatures, and challenging terrain.
- AMSOIL OE Fuel-Efficient 100% Synthetic Automatic Transmission Fluid – An excellent OE alternative that protects against wear and maintains shift quality.
- AMSOIL Passenger Car & Light Truck Antifreeze & Coolant – A phosphate-, nitrate-, and silicate-free ethylene glycol formulation that protects the cooling system up to 150,000 miles or 5 years.
- AMSOIL Propylene Glycol Antifreeze and Engine Coolant – A concentrated option requiring mixing, offering extended protection up to 1,000,000 miles in heavy-duty applications and surpassing OEM standards for corrosion resistance.
- AMSOIL DOT 3 and DOT 4 100% Synthetic Brake Fluid – Delivers excellent ABS responsiveness and stable viscosity across a wide temperature range, meeting MB Sheet 331.0 requirements.
- AMSOIL 100% Synthetic Multi-Vehicle Power Steering Fluid – Formulated to keep seals soft, prevent leaks, and ensure quiet operation while resisting heat degradation.
Why Synthetic Fluids Are Critical for the CL550
The 5.5-liter M273 V8 engine in the 2007 CL550 is a masterpiece of internal combustion engineering, but it relies heavily on the quality of its lubricants. Factory fill oils and mineral-based coolants often begin to degrade well before the recommended service intervals, leaving the engine vulnerable to sludge, varnish, and thermal breakdown. AMSOIL synthetic European motor oils utilize advanced additive packages and base oil formulations specifically calibrated for German engines. They reduce friction more effectively than conventional oils, which translates to reduced wear on critical components like timing chains, camshafts, and bearings.
Furthermore, the 7-speed automatic transmission (722.9) is a sensitive component that benefits immensely from synthetic fluid. The fluid in this system must handle rapid shifts and high torque loads without foaming or losing its viscosity. The AMSOIL Signature Series and OE Fuel-Efficient transmission fluids provide a level of friction modification and thermal stability that extends the life of the transmission solenoids and clutch packs. With a total fill capacity of 10.4 quarts for a complete change, using the correct fluid is essential for maintaining the vehicle’s smooth power delivery.
Complete Lubrication Coverage
Beyond the engine and transmission, the CL550 requires a holistic approach to maintenance. The cooling system holds 12.7 quarts of fluid, making the choice of antifreeze significant. Conventional green antifreeze can break down over time, leading to corrosion in the aluminum radiators and water pumps. AMSOIL Antifreeze and Coolant provides long-term protection against freezing and boiling, safeguarding the engine from thermal shock. Additionally, the brake fluid in a high-performance vehicle like the CL550 must resist moisture absorption, which can lower the boiling point and cause brake fade. Our synthetic DOT 3/DOT 4 brake fluid maintains a high boiling point, ensuring consistent pedal feel in all conditions.
About the Vehicle: 2007 Mercedes-Benz CL550
The 2007 Mercedes-Benz CL550 represents a high point in the brand’s coupe lineage, sitting as the luxurious two-door counterpart to the S-Class sedan. Based on the W216 platform, it was introduced to bridge the gap between the CLK and the high-performance CL 600. Under the hood, the CL550 is powered by the 5.5-liter V8 M273 engine, a naturally aspirated powerhouse that delivers smooth, linear power rather than the sudden torque of a turbocharged unit. This engine is renowned for its durability when maintained with high-quality synthetic lubricants, capable of exceeding high mileage thresholds without major issues.
Owners of the CL550 appreciate its blend of grand tourer comfort and sporty character. The interior features high-end materials, including premium leather and wood trim, offering a sanctuary of quiet and isolation from the road. The chassis is tuned for stability at high speeds, making it a preferred vehicle for long-distance travel on the Autobahn or winding backroads. Despite its size, the car remains agile, thanks to the precise steering and sophisticated suspension systems. The vehicle was positioned as a luxury coupe for those who wanted the exclusivity of a two-door design without the absolute price tag of the V12 models, making it a sought-after choice for enthusiasts who value refinement over raw horsepower numbers.
Common Issues and Solutions
Like any vehicle of this complexity and age, the CL550 has known failure points that can be mitigated with proper maintenance. One common issue involves the cooling system, where old hoses and gaskets may develop leaks or where thermal stress can cause aluminum cracks. Using a high-quality synthetic coolant like AMSOIL Propylene Glycol or the pre-mixed Passenger Car coolant can significantly reduce the risk of corrosion and overheating, protecting the integrity of the block and radiator.
Another area of concern is the oil consumption and potential oil leakage from valve cover gaskets or the crankshaft seal, which can become brittle over time. AMSOIL synthetic oils provide better sealing properties and resist the harsh thermal cycles that cause gaskets to shrink or harden, potentially slowing the rate of leaks and reducing the frequency of top-offs. Additionally, the high-mileage design of these synthetic fluids helps condition seals, making them more pliable and less prone to cracking.
Furthermore, the 7-speed automatic transmission can sometimes experience shudder or harsh shifts if the fluid has degraded. Regular fluid changes using a premium synthetic transmission fluid can clear up these symptoms by removing varnish from the valve body and ensuring smooth hydraulic pressure. Finally, the fuel system, particularly the injectors on a high-compression V8, can suffer from carbon buildup and ethanol-related corrosion over the years. Periodic use of an additive like AMSOIL P.i. can help restore fuel injector flow, recover lost horsepower, and improve overall engine smoothness and efficiency.