The 2018 Mercedes-Benz CLS63 AMG S represents the pinnacle of performance engineering, pairing the luxury of a sleek coupe with the raw power of a twin-turbocharged V8. Owners of this high-performance vehicle understand that standard automotive fluids simply cannot withstand the extreme thermal and mechanical stresses generated by a 5.5L 8-cylinder engine code 157.98.6 Turbo. Using the correct lubricants is not merely a maintenance task; it is a critical component of preserving the vehicle’s longevity, performance, and safety. Synthetic formulations are required to handle the intense heat of the AMG powertrain, ensuring that critical components like pistons, turbochargers, and transmission clutches operate within optimal parameters.
Recommended AMSOIL Products
To maintain the superior performance of your 2018 CLS63 AMG S, AMSOIL offers a complete line of premium lubricants designed specifically for the rigorous demands of German engineering. These products exceed original equipment manufacturer specifications and are formulated to provide extended protection against sludge, varnish, and thermal breakdown.
- AMSOIL 5W-40 FS 100% Synthetic European Motor Oil – Specifically engineered for gasoline, diesel, and hybrid European vehicles, this oil features a precise blend of synthetic base oils and premium additives to handle high-performance engines.
- AMSOIL 0W-40 FS 100% Synthetic European Motor Oil – An alternative viscosity option designed for the unique demands of European vehicles, offering superior flow in extreme cold and robust protection at high temperatures.
- AMSOIL Signature Series Fuel-Efficient 100% Synthetic Automatic Transmission Fluid – Provides maximum protection for the 7-speed transmission (722.971), withstanding heavy towing, elevated temperatures, and challenging terrain while remaining fluid in sub-zero conditions.
- AMSOIL OE Fuel-Efficient 100% Synthetic Automatic Transmission Fluid – A cost-effective option that still delivers essential protection against wear for the automatic transmission system.
- AMSOIL Passenger Car & Light Truck Antifreeze & Coolant – A unique poly-organic acid formulation that protects cooling system metals, gaskets, and hoses, compatible with all other antifreeze colors.
- AMSOIL Propylene Glycol Antifreeze and Engine Coolant – A concentrated option that requires mixing with water, offering exceptional protection against corrosion and erosion, extending service intervals significantly.
- 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 for safe stopping power.
- AMSOIL 100% Synthetic Multi-Vehicle Power Steering Fluid – Helps seals remain soft to prevent leaks and resists heat for long fluid life, ensuring quiet and smooth steering operation.
- AMSOIL P.i. Performance Improver – A gasoline additive that restores up to 14% horsepower, cleans GDI fuel injectors, and reduces the need for costly higher-octane fuel.
Proper fluid selection is vital because the 2018 CLS63 AMG S operates under conditions that would quickly degrade conventional oils. The twin-turbo 5.5L engine generates immense heat, and the transmission must handle rapid shifts and high torque. AMSOIL products are designed to resist shear and thermal breakdown, ensuring that your vehicle maintains its factory performance characteristics for a longer duration. By using these premium fluids, you reduce friction, minimize wear on critical components, and help extend the service intervals between maintenance, providing peace of mind for your daily drive or weekend track sessions.
Engine and Transmission Lubrication Details
The heart of the 2018 Mercedes-Benz CLS63 AMG S is the 5.5-liter V8 engine, designated by engine code 157.98.6. This powerplant is a marvel of German engineering, and it demands the highest quality of protection. For the crankcase, AMSOIL recommends a capacity of 9 quarts when including the oil filter. It is crucial to check the oil level after the refill to ensure the correct volume is present, as under-filling can lead to catastrophic failure. When performing the oil change, pay close attention to the drain plug torque specifications: plastic plugs should be torqued to 3 ft-lbs, M12 bolts to 15 ft-lbs, and M14 bolts to 22 ft-lbs.
For the engine oil, two distinct viscosity grades are suitable depending on your driving climate and preferences. The AMSOIL 5W-40 FS 100% Synthetic European Motor Oil offers an excellent balance for a wide range of temperatures, specifically recommended for conditions above -25°C. For drivers facing severe cold or those who prioritize maximum immediate flow upon startup, the AMSOIL 0W-40 FS 100% Synthetic European Motor Oil is a superior choice. Both oils are designed with a European formula featuring a precise blend of synthetic base oils and premium additives that exceed OEM requirements.
The automatic transmission, a 7-speed unit (722.971…), is another critical component requiring specialized attention. The total fill capacity for the 7-speed transmission is 8.2 quarts. It is important to note the distinction in transmission fluid requirements based on the presence of the A89 code (Reduced-Friction) on your vehicle’s datacard. For units with the A89 code, or standard operation without it, the AMSOIL Signature Series Fuel-Efficient 100% Synthetic Automatic Transmission Fluid provides exceptional resistance to heat and shear. Alternatively, the AMSOIL OE Fuel-Efficient 100% Synthetic Automatic Transmission Fluid offers robust protection against wear for the clutch packs and torque converter.
Cooling and Safety Systems
Maintaining the correct operating temperature is essential for the longevity of the AMG’s engine. The cooling system has a specific capacity, with the High-Temperature Cooling Circuit (HTCC) requiring 9 quarts and the Low-Temperature Cooling Circuit (LTCC) requiring 2.5 quarts. To ensure compatibility and maximum protection, the AMSOIL Passenger Car & Light Truck Antifreeze & Coolant is an ethylene glycol 50/50 pre-mix formulation. It is phosphate-, nitrate-, nitrite-, silicate-, borate-, and amine-free, ensuring it will not harm gaskets or hoses. For those who prefer a concentrated solution, the AMSOIL Propylene Glycol Antifreeze and Engine Coolant provides up to 150,000 miles or 5 years of protection in passenger cars and light trucks.
Safety is paramount in a vehicle capable of such high speeds, making the braking system a critical area of focus. The recommended fluid is a DOT 4 plus standard. The AMSOIL DOT 3 and DOT 4 100% Synthetic Brake Fluid offers a stable viscosity over a wide temperature range, ensuring consistent pedal feel and responsiveness. For the steering system, which may require specific fluid formulations, the AMSOIL 100% Synthetic Multi-Vehicle Power Steering Fluid helps seals remain soft to prevent leaks and resists heat for long fluid life, contributing to a quiet and smooth ride.
For owners looking to optimize fuel economy and engine performance, the AMSOIL P.i. Performance Improver is a powerful gasoline additive. It restores up to 14% horsepower and cleans fuel injectors to 100% flow rate, making it an excellent addition to your maintenance regimen. Additionally, for seasonal storage, products like AMSOIL Gasoline Stabilizer can keep fuel fresh for up to 12 months, protecting the engine from varnish and gum buildup.
Vehicle Background and Performance History
The 2018 Mercedes-Benz CLS63 AMG S occupies a unique and prestigious position in the automotive landscape. It is a four-door coupe that blends the sleek, aerodynamic silhouette of a luxury sports car with the practicality of a sedan. Produced under the Mercedes-AMG marque, the CLS63 is a high-performance variant that serves as the “sporty” alternative to the standard CLS, offering drivers an aggressive driving experience without sacrificing the ride comfort associated with the Mercedes-Benz brand.
This model year features the M178 5.5-liter V8 twin-scroll turbocharged engine, which is a significant evolution of Mercedes’ AMG “Biturbo” technology. The engine, identified by the internal code 157.98.6, delivers an astounding 603 horsepower and 664 lb-ft of torque in the S model. This powertrain allows the vehicle to accelerate from 0 to 60 mph in roughly 3.4 seconds, placing it among the fastest production sedans of its time. The driving character is defined by a blend of ferocious straight-line speed and refined handling, thanks to the AMG Speedshift DCT 7-speed automatic transmission and the sophisticated 4MATIC all-wheel-drive system.
The CLS63 AMG S is part of the X218 generation, which was known for its sharp lines and distinctive “floating” roof design. It appealed to buyers who wanted a vehicle that looked fast even when parked. The interior reflects its performance status with premium materials, sport seats, and advanced technology features. The platform was designed to handle high-speed stability, with a lower center of gravity compared to traditional sedans, providing a more engaging driving dynamic.
While the vehicle is renowned for its performance, owners of the 2018 CLS63 AMG S should be aware of common issues that can arise with high-mileage AMG models. The first common concern is turbocharger wear. The twin-scroll turbos operate at extremely high temperatures and rotational speeds. Over time, oil coking can occur if the vehicle is not allowed to cool down properly after aggressive driving or if inferior oil is used. The use of high-quality synthetic motor oil like AMSOIL can help mitigate this by providing superior thermal stability and reducing carbon buildup on turbine bearings.
Another frequent problem involves the direct injection system, particularly carbon buildup on the intake valves. Because these engines use direct injection, fuel does not wash over the valves, leading to the accumulation of carbon deposits over time. This can result in rough idling, misfires, and a loss of power. Regular use of a high-quality fuel system cleaner like AMSOIL P.i. can help clean these injectors and prevent carbon deposits from forming, restoring lost horsepower and fuel efficiency.
A third issue often seen in high-performance AMG models is transmission fluid degradation. The heavy loads and rapid shifts can cause the transmission fluid to break down faster than in standard vehicles. This can lead to delayed shifts, shuddering, or a noticeable drop in transmission performance. Using a full-synthetic transmission fluid designed for high-performance applications ensures the clutches and bands remain protected, preventing premature wear and maintaining the crisp shift quality the vehicle was designed for.
Finally, cooling system integrity is critical for the long-term health of the V8 engine. The high thermal output of the twin-turbo setup places immense stress on the cooling system. Over time, standard coolants can lose their corrosion inhibitors, leading to leaks or overheating. Using a premium antifreeze with extended life properties helps protect the aluminum engine block and various cooling components from corrosion, ensuring the engine stays at the correct operating temperature and avoids costly overheating repairs.
Owners of the 2018 CLS63 AMG S who wish to maintain their vehicle’s exceptional performance should consider a comprehensive approach to fluid maintenance. By selecting the right AMSOIL products, you are not just changing fluids; you are investing in the longevity and performance of one of the most capable vehicles on the road. Whether you are commuting daily or taking the car to a track day, the proper lubricants will ensure that your AMG performs as intended, providing a safe and exhilarating driving experience for years to come.