The 2021 Mercedes-Benz CLS450 is a sophisticated four-door coupe that blends sporty performance with elegant design. Under the hood, the CLS450 is powered by a 3.0-liter inline-six engine equipped with a twin-scroll turbocharger and an electric integrated starter generator. This advanced powertrain, identified by engine code 256.930.2, delivers robust power and efficiency but demands specific lubrication standards to maintain its precise engineering and longevity. Using fluids that do not meet the vehicle’s strict OEM requirements can lead to increased wear, reduced fuel economy, and potential issues with sensitive emission systems. Proper lubrication is the single most effective way to protect this high-stress turbocharged engine, especially for owners who subject their vehicle to extreme temperatures, frequent stop-and-go traffic, or long highway hauls.
Recommended AMSOIL Products
For the 2021 Mercedes Benz CLS450, AMSOIL offers a comprehensive line of synthetic lubricants designed to exceed original equipment manufacturer specifications. The following products provide the protection needed for the engine, transmission, cooling system, and braking components.
- AMSOIL 5W-30 LS 100% Synthetic European Motor Oil – A specialized formula designed for the unique demands of gasoline, diesel, and hybrid European vehicles, featuring a precise blend of synthetic base oils and premium additives.
- AMSOIL 5W-40 MS 100% Synthetic European Motor Oil – Engineered for high-performance European engines, offering superior protection against the high thermal and mechanical stresses of the CLS450’s turbocharged 3.0L engine.
- AMSOIL 0W-20 LS 100% Synthetic European Motor Oil – An ultra-low viscosity option that ensures rapid oil flow during cold starts while maintaining a robust film at operating temperatures, suitable for extreme temperature ranges.
- AMSOIL Passenger Car & Light Truck Antifreeze & Coolant – A unique poly-organic acid (OAT) formulation that protects all cooling system metals, gaskets, and hoses, extending service life up to 150,000 miles or five years.
- AMSOIL Propylene Glycol Antifreeze and Engine Coolant – A concentrated option that requires mixing with distilled water, offering extended protection up to 150,000 miles and greatly surpassing standards for metallic corrosion and erosion.
- AMSOIL Signature Series Fuel-Efficient 100% Synthetic Automatic Transmission Fluid – Withstands the rigors of heavy towing, elevated temperatures, and challenging terrain while remaining fluid in sub-zero conditions.
- AMSOIL OE Fuel-Efficient 100% Synthetic Automatic Transmission Fluid – Provides excellent wear protection and efficiency for automatic transmissions, meeting the specific needs of European drivetrains.
- AMSOIL DOT 3 and DOT 4 100% Synthetic Brake Fluid – Delivers excellent ABS and traction-control responsiveness with a stable viscosity over a wide temperature range, compatible with MB Sheet 331.0 requirements.
Engine Oil and Filter Specifications
The 2021 Mercedes-Benz CLS450 utilizes a 3.0-liter inline-six turbocharged engine that requires precise oil viscosity to ensure optimal lubrication across all operating conditions. The manufacturer specifies an oil capacity of 9 quarts when including a filter change. After refilling, it is critical to check the oil level to ensure the proper fill volume. The recommended viscosity grades include 0W-20, 0W-30, and 0W-40 for all temperatures, as well as 5W-30 and 5W-40 for temperatures above -25°C. Maintaining the correct viscosity is essential for the engine’s Variable Valve Timing (VVT) system and turbocharger bearing protection.
While no specific oil filter recommendation is available in the source data, the use of high-grade synthetic oil helps extend the life of any compatible filter by reducing soot buildup and preventing the formation of sludge that can clog filtration systems. Regular oil changes using AMSOIL synthetic motor oils ensure that the engine stays clean and runs smoothly, reducing the risk of carbon buildup on turbocharger bearings and piston rings.
Transmission and Differential Fluids
The automatic transmission in the CLS450 operates under significant thermal stress, particularly given the vehicle’s sport-oriented nature. AMSOIL offers two primary options for transmission fluid: the Signature Series Fuel-Efficient 100% Synthetic Automatic Transmission Fluid and the OE Fuel-Efficient 100% Synthetic Automatic Transmission Fluid. Both products are formulated to protect against wear, sludge, and temperature-related problems, ensuring smooth shifting and extended transmission life.
The transfer case and differential components also require specific attention. For the transfer case, the capacity is listed as approximately 1.5 pints. When servicing the transfer case, care must be taken to torque the fill plug to 10 ft-lbs and the drain plug to 18 ft-lbs to prevent leaks and ensure proper sealing. The differential capacity varies by position, with the front requiring approximately 1.3 pints. Using a synthetic gear lube designed for these components helps prevent wear and ensures smooth power delivery to the wheels, which is vital for the CLS450’s all-wheel-drive capabilities.
Cooling and Brake Systems
The cooling system is a critical component for a turbocharged engine like the 3.0L M256 in the CLS450. AMSOIL provides two antifreeze options to match different maintenance preferences. The Passenger Car & Light Truck Antifreeze & Coolant comes as a 50/50 pre-mix, making it convenient for a direct pour, while the Propylene Glycol Antifreeze is a concentrated formula that offers longer service intervals and requires mixing with distilled water. The system capacity is substantial, requiring 12.7 quarts of high-temperature coolant and 3.2 quarts of low-temperature coolant to ensure the engine stays within its optimal operating temperature range.
For the braking system, the CLS450 requires DOT 4 brake fluid that meets MB Sheet 331.0 specifications. The AMSOIL DOT 3 and DOT 4 100% Synthetic Brake Fluid is an excellent choice, offering high boiling points to prevent brake fade under heavy use and providing excellent ABS responsiveness. This fluid is compatible with the vehicle’s sensitive electronic stability control systems and helps maintain a consistent pedal feel throughout the fluid’s service life.
Why Owners Like This Vehicle
The 2021 Mercedes-Benz CLS450 occupies a unique niche in the automotive market as a four-door coupe. Unlike a traditional sedan, the CLS450 features a sloping roofline and a more aggressive stance, giving it a sportier silhouette that rivals actual sports cars. At the same time, it retains the practicality of a full-sized four-door vehicle, making it a popular choice for individuals who want the look of a coupe without sacrificing rear passenger access or cargo space. The vehicle is built on the MRA (Modular Rear Architecture) platform, which allows for a lightweight construction that contributes to its dynamic handling and agility.
Performance enthusiasts appreciate the CLS450’s 3.0-liter inline-six turbocharged engine, which produces a robust combination of power and torque. The 48-volt mild-hybrid system, often referred to as EQ Boost, provides an extra 21 horsepower and 184 lb-ft of torque on demand, enhancing acceleration and smoothing out stop-and-go traffic. This technology also allows for a smoother start-stop system, reducing emissions and improving fuel efficiency. The driving character is a blend of comfort and performance, with adjustable suspension settings that allow the driver to switch between a comfortable ride and a sportier handling mode. This versatility makes the CLS450 suitable for daily commuting as well as spirited weekend drives.
Despite its sophisticated engineering, the CLS450 does face some common issues that owners should be aware of. One frequent complaint involves the 48-volt battery and integrated starter-generator, which can sometimes fail and trigger warning lights. Regular use of high-quality electrical systems and proper oil levels can help mitigate the strain on the electrical components. Another common problem is related to the Airmatic suspension system, where air struts may develop leaks over time, leading to sagging or uneven ride height. While oil doesn’t fix suspension leaks, proper lubrication of all chassis components can help maintain overall vehicle health. Some owners report issues with the infotainment system lagging or freezing, which is a software-related concern but can be managed with regular updates. Finally, the dual-clutch transmission in some models may experience jerky shifts during low-speed maneuvers. Using a high-quality synthetic transmission fluid like the AMSOIL Signature Series can help lubricate the clutches more effectively, potentially reducing these shift shocks and improving overall transmission smoothness.
About the Vehicle
The Mercedes-Benz CLS450 represents a bold statement in the luxury automotive world. Introduced as a four-door coupe, it has successfully bridged the gap between style and functionality. The 2021 model year continues the legacy of the CLS lineup, which has been a staple of the Mercedes-Benz brand for over a decade. The vehicle is known for its sleek, aerodynamic design, which not only looks stunning but also contributes to its on-road performance by reducing drag.
The 3.0L inline-six engine is a masterpiece of modern engineering. Part of the M256 engine family, it incorporates a belt-driven electric supercharger that works in tandem with the traditional turbocharger. This dual-boost system ensures that there is no lag, providing immediate power response regardless of engine speed. The engine is paired with a 9-speed automatic transmission that is tuned for smooth, seamless shifts, further enhancing the driving experience. The interior of the CLS450 is equally impressive, featuring high-quality materials, advanced technology, and a driver-focused cockpit that emphasizes comfort and luxury.
The CLS450 is often compared to other luxury sedans like the BMW 5 Series and the Audi A7. However, its unique profile sets it apart. It appeals to drivers who want the prestige of a German luxury brand but desire a vehicle with a more distinctive appearance. The vehicle is manufactured in Bremen, Germany, a city with a long history of automotive excellence. The CLS450 is a testament to Mercedes-Benz’s commitment to innovation, combining cutting-edge technology with timeless design principles. Whether for business or pleasure, the CLS450 offers a driving experience that is both luxurious and engaging.
Extended Life Protection
By choosing AMSOIL synthetic lubricants, owners of the 2021 Mercedes-Benz CLS450 can enjoy extended drain intervals and superior protection against the elements. Unlike conventional oils, AMSOIL synthetic motor oils are resistant to breakdown at high temperatures and flow more freely in cold conditions. This results in faster lubrication of engine components upon startup, reducing wear and tear. The use of AMSOIL antifreeze and coolant also provides excellent corrosion protection, ensuring the cooling system remains clean and efficient for years.
In conclusion, the 2021 Mercedes-Benz CLS450 is a remarkable vehicle that deserves the best care possible. By following the recommended fluid specifications and utilizing AMSOIL’s high-performance synthetic lubricants, owners can ensure their vehicle operates at peak performance for the long haul. From the engine’s internal components to the transmission and cooling systems, every part of the CLS450 benefits from the advanced technology found in AMSOIL products. Whether you are driving in extreme heat or cold, the reliability and protection provided by these synthetic fluids make them the ideal choice for this sophisticated machine.