The 2012 Mercedes-Benz SLK55 AMG represents the pinnacle of the company’s high-performance roadsters, combining the open-air freedom of a convertible with the raw power of a naturally aspirated V8. Under the hood lies the impressive 5.5-liter M152 engine, a hand-built powerplant that delivers significant horsepower and torque without the need for forced induction. To keep this sophisticated machine running at peak performance, owners require lubrication solutions that meet rigorous OEM standards while providing superior protection against wear, heat, and the demands of spirited driving. Using the correct fluids is essential for maintaining the longevity of the engine, cooling system, transmission, and other critical systems.
Recommended AMSOIL Products
- AMSOIL 5W-40 FS 100% Synthetic European Motor Oil – A premium synthetic lubricant designed specifically for the unique demands of European gasoline, diesel, and hybrid vehicles, featuring a precise blend of base oils and additives for optimal protection.
- AMSOIL 0W-40 FS 100% Synthetic European Motor Oil – An alternative viscosity option for the same European formula, offering exceptional cold-start performance while maintaining the high thermal stability required by the SLK55’s high-revving engine.
- AMSOIL Passenger Car & Light Truck Antifreeze & Coolant – A ready-to-use 50/50 ethylene glycol pre-mix formulation that protects all cooling system metals, gaskets, and hoses while exceeding original equipment manufacturer requirements.
- AMSOIL Propylene Glycol Antifreeze and Engine Coolant – A concentrated, non-toxic antifreeze option that requires mixing with water, offering extended protection against corrosion, erosion, and boiling over for up to 150,000 miles or 5 years.
- AMSOIL Signature Series Fuel-Efficient 100% Synthetic Automatic Transmission Fluid – A high-performance fluid engineered to withstand 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 – A cost-effective yet superior synthetic option that provides excellent protection against wear for the 722.9 transmission used in this vehicle.
- AMSOIL DOT 3 and DOT 4 100% Synthetic Brake Fluid – A fluid formulated for excellent ABS and traction-control responsiveness with stable viscosity over a wide temperature range, meeting MB Sheet 331.0 standards.
- AMSOIL 100% Synthetic Multi-Vehicle Power Steering Fluid – Designed to reduce friction and prevent leaks by keeping seals soft, while providing strong anti-wear protection and resistance to heat for long fluid life.
Engine Oil and Capacity Specifications
Proper lubrication is the lifeblood of the 2012 SLK55 AMG’s 5.5-liter V8 engine. The engine code 152.980 I requires a motor oil that can handle extreme thermal loads while maintaining viscosity to ensure a strong lubricating film between moving parts. AMSOIL 5W-40 FS 100% Synthetic European Motor Oil and AMSOIL 0W-40 FS 100% Synthetic European Motor Oil are engineered to provide maximum protection against sludge, varnish, and wear, regardless of whether you are commuting in traffic or enjoying a track day.
The oil capacity for this vehicle is approximately 10 quarts when performing a complete change with a filter replacement. It is crucial to observe the correct refill procedures; after refilling, you must check the oil level to ensure the sump is at the appropriate fill point. The torque specification for the oil drain plug is 22 ft-lbs, a detail that should be followed to prevent galling the aluminum pan or stripping the threads. Owners have the flexibility to choose between two distinct viscosities for this engine: 5W-40 and 0W-40. Both are available in the AMSOIL FS (Formula Synthetic) European Motor Oil line, ensuring compatibility with European engine tolerances and performance requirements.
Transmission and Differential Maintenance
The SLK55 AMG is equipped with a 7-speed automatic transmission (model 722.9), which relies on precise fluid dynamics to operate its multiple clutch packs and gears. Using a fluid that degrades quickly under heat can lead to harsh shifting, delayed engagement, and eventual internal failure. AMSOIL offers two primary transmission fluid options for this application. The AMSOIL Signature Series Fuel-Efficient 100% Synthetic Automatic Transmission Fluid is ideal for those seeking maximum performance and extended drain intervals, while the AMSOIL OE Fuel-Efficient 100% Synthetic Automatic Transmission Fluid offers a highly effective alternative for routine maintenance.
The total fill capacity for the transmission varies depending on the specific data card configuration. For models equipped with the A89 reduced-friction code, or those without specific codes, the total fill capacity is 9.5 quarts for the 7-speed 722.9 transmission. Regular fluid changes are vital for preventing the buildup of metallic debris and sludge that can clog solenoids and valves. The Signature Series fluid remains fluid in sub-zero temperatures while providing a protective film that reduces friction and heat, extending the service life of the transmission.
Cooling System and Fluids
Maintaining the cooling system is critical for a high-performance engine like the M152 V8, which generates substantial heat. The 2012 SLK55 AMG requires a AMSOIL Passenger Car & Light Truck Antifreeze & Coolant that provides robust freeze and boil-over protection while safeguarding the aluminum components and rubber hoses of the cooling system. The system capacity is approximately 10 quarts. Owners can choose between the AMSOIL Passenger Car & Light Truck Antifreeze & Coolant, which is a convenient 50/50 pre-mix, or the concentrated AMSOIL Propylene Glycol Antifreeze and Engine Coolant.
The AMSOIL Propylene Glycol Antifreeze and Engine Coolant is a non-toxic alternative that requires mixing with distilled water. It offers superior protection against metallic corrosion and erosion, often surpassing the standards set by original equipment manufacturers. Its phosphate-, nitrate-, nitrite-, silicate-, borate-, and amine-free composition ensures compatibility with all other coolant colors and materials, preventing chemical reactions that can lead to cavitation or seal damage. Whether you opt for the ethylene glycol or propylene glycol version, the result is a cooling system that operates efficiently across a wide temperature range, keeping your engine within safe operating limits.
Brake, Steering, and Seasonal Care
Safety systems like brakes and power steering require specialized fluids to function correctly and reliably. The SLK55 AMG utilizes a hydraulic braking system that benefits from the high boiling point and stability of AMSOIL DOT 3 and DOT 4 100% Synthetic Brake Fluid. This fluid ensures excellent responsiveness from the ABS and traction control systems, even during repeated heavy braking events. It provides a stable viscosity over a wide temperature range, preventing the fluid from boiling and causing a spongy pedal feel.
Similarly, the power steering system operates under high pressure and requires a fluid that reduces friction and protects seals. The AMSOIL 100% Synthetic Multi-Vehicle Power Steering Fluid is formulated to keep seals soft to prevent leaks, while resisting heat for extended fluid life. It also offers low-temperature performance and high-temperature protection, ensuring quiet operation and precise steering control.
Model History and Performance
The 2012 Mercedes-Benz SLK55 AMG occupies a unique space in the automotive landscape as a compact luxury roadster. Part of the R172 platform (though the SLK55 is often associated with the R171 generation, the 2012 model year sits on the 5.5L M152 engine often found in the 2009-2011 SLK55 AMG which continued into the early 2012 production year before the model line evolved), this vehicle was built to offer an accessible entry point into the world of AMG performance. The SLK55 AMG was distinguished by its hand-crafted 5.5-liter V8 engine, which produced roughly 382 horsepower and 391 lb-ft of torque. Unlike many of its contemporaries that relied on turbochargers or superchargers to boost power, the SLK55’s naturally aspirated engine provided a distinct, high-pitched roar and linear power delivery that enthusiasts cherished.
The car was known for its versatility, functioning as a practical two-seater with a folding hardtop that could stow away in seconds, transforming the coupe into an open-top roadster. This mechanical innovation, combined with the raw power of the V8, made it a favorite among driving enthusiasts who valued both performance and daily usability. The chassis was tuned to provide sharp handling characteristics, making it a capable performer on winding roads and the occasional track day. Owners of this vehicle often appreciate its balance of luxury, performance, and the unique engineering of the AMG division, which added exclusive features like specific suspension tuning and exhaust notes to the standard SLK experience. Keeping this engine and transmission healthy through regular maintenance ensures that this driver-focused roadster continues to provide the dynamic driving experience it was designed for.