Maintaining the performance and longevity of your 2008 Audi RS4 requires more than just standard maintenance; it demands precision-engineered lubricants designed specifically for high-output European powertrains. This vehicle, equipped with the naturally aspirated 4.2L V8 engine (Engine Code BNS S), operates under significant thermal and mechanical stress that standard oils may not adequately address. Proper fluid selection ensures optimal protection against wear, reduces friction in the drivetrain, and maintains the vehicle’s renowned driving dynamics over years of use.
Recommended AMSOIL Products
- AMSOIL 5W-40 MS 100% Synthetic European Motor Oil – A specialized formula designed for the precise demands of gasoline, diesel, and hybrid European vehicles, featuring a blend of synthetic base oils and premium additives to meet Audi and Volkswagen standards.
- AMSOIL 5W-40 FS 100% Synthetic European Motor Oil – Engineered to protect high-stress European engines, this oil offers superior thermal stability and wear protection while ensuring compliance with the required quality standards for the RS4.
- AMSOIL 0W-40 FS 100% Synthetic European Motor Oil – Ideal for extreme temperature conditions, this synthetic oil provides rapid flow during cold starts and maintains a protective film at operating temperatures, ensuring longevity for your V8 powerplant.
- MANN-FILTERS Oil Filter – A high-efficiency filtration solution that offers improvements over original equipment manufacturer branded filters, capturing contaminants to keep engine oil clean and extend service intervals.
- AMSOIL Passenger Car & Light Truck Antifreeze & Coolant – A unique OAT formulation that protects the cooling system metals, gaskets, and hoses while providing up to 150,000 miles or 5 years of protection in a 50/50 pre-mix.
- AMSOIL 75W-90 Manual Transmission & Transaxle Gear Lube – Formulated to protect brass synchronizers and withstand high heat and pressure, this friction-modified fluid ensures smooth shifting and long service life for the manual transmission.
- AMSOIL DOT 3 and DOT 4 100% Synthetic Brake Fluid – Delivers excellent ABS and traction-control responsiveness with a stable viscosity across a wide temperature range, meeting the strict hydraulic requirements of the RS4 braking system.
- AMSOIL 75W-90 Long Life 100% Synthetic Gear Lube – Engineered for high-load gear and bearing protection in the rear differential, this fluid resists rust and corrosion while improving seal life and cold-weather shifting performance.
- AMSOIL 100% Synthetic Multi-Vehicle Power Steering Fluid – Helps seals remain soft to prevent leaks while providing strong anti-wear protection and excellent high-temperature performance for quiet operation.
The 2008 Audi RS4 stands as a benchmark in the high-performance segment, particularly in its sedan form. Powered by the legendary 4.2-liter V8 engine, this model delivers a raw, naturally aspirated power curve that distinguishes it from the turbocharged variants that became common in later years. The engine code BNS S drives a manual transmission in many configurations, offering a tactile driving experience that engages the driver through precise shifts and a responsive clutch. This combination of a high-revving engine and a short-ratio gearbox creates a car that feels equally at home on a winding mountain road as it does on a daily commute, provided it receives the correct care.
When it comes to the engine, the 4.2L V8 is a robust unit, but like all high-compression engines, it generates significant heat. The recommended oil capacity for a complete service, including the filter, is 10 quarts. Ensuring the correct volume is used is crucial; an overfill or underfill can lead to aeration issues or insufficient lubrication. Using a viscosity suitable for your local climate, whether that is a 0W-40 for colder regions or a 5W-40 for warmer conditions, is essential for maintaining the engine’s health. The engine also requires the oil drain plug to be torqued to 18 ft/lbs to prevent leaks and ensure a tight seal.
Beyond the engine, the transmission system requires specific attention. For the manual gearbox, the capacity is 6.8 pints, with the fill plug requiring a torque of 30 ft/lbs. This gearbox benefits significantly from the specialized shear stability and friction modification of AMSOIL’s 75W-90 Manual Transmission & Transaxle Gear Lube, which protects the synchronizers during aggressive shifts. The rear differential is a high-performance unit that houses a limited-slip mechanism, requiring a fluid like the Long Life 100% Synthetic Gear Lube to handle the increased load and heat. The capacity for the rear differential is 1.9 pints. Regularly changing these fluids ensures that the distinct driving character of the RS4 is preserved and that the drivetrain operates with minimal resistance.
The cooling system is another critical area. With a capacity of 12.2 quarts, the RS4’s radiator and intercooler system requires a coolant that offers superior corrosion protection for its aluminum components. The AMSOIL Passenger Car & Light Truck Antifreeze & Coolant provides this protection while avoiding harmful additives like silicates and phosphates that can harm the seals and metal surfaces over time. Alternatively, the AMSOIL Propylene Glycol Antifreeze and Engine Coolant is an excellent concentrated option. Additionally, the hydraulic systems, including the brake fluid and power steering, demand high-performance fluids to maintain safety and control. The brake fluid must meet DOT 4 standards to prevent boil-over during hard braking, while the AMSOIL 100% Synthetic Multi-Vehicle Power Steering Fluid must resist heat breakdown to ensure smooth steering assist throughout the vehicle’s life cycle.
Owners of the 2008 RS4 often appreciate the vehicle’s balance of everyday usability and track capability. It is a car that rewards attentive driving and proper maintenance. By adhering to the specific fluid recommendations and capacities outlined for this model, owners can maximize the potential of their vehicle, ensuring that the iconic 4.2L V8 continues to deliver its signature power and the chassis maintains its precise handling. From the engine block to the differential, every component benefits from the advanced protection offered by these premium synthetic lubricants.
About the Vehicle
The 2008 Audi RS4 is a testament to engineering excellence, representing a specific era of performance sedans that prioritized high-revving naturally aspirated power over forced induction. Based on the B7 platform, this model featured a hand-assembled 4.2-liter V8 engine that was a favorite among enthusiasts for its linear power delivery and sonorous exhaust note. Unlike the supercharged models that preceded it, the 2008 iteration offered a unique driving character that required skill to master, particularly when mated to the six-speed manual transmission.
The vehicle was built at Audi’s Ingolstadt plant and quickly gained a reputation for being a “sleeper,” capable of surprising rivals on the road and the track with its acceleration and handling dynamics. The RS4 was designed to be a practical performance car, offering a usable trunk and four comfortable seats, yet it retained the aggressive styling and stiff suspension geometry necessary for spirited driving. Owners often cite the direct feel of the manual shifter and the precise steering as key reasons for loving this model.
While the car is now over a decade old, its mechanical simplicity compared to modern turbocharged engines makes it an attractive candidate for maintenance and longevity. The focus is less on complex electronics and more on the mechanical integrity of the drivetrain. Regular maintenance, particularly of the fluids that lubricate the engine, transmission, and differential, is the key to keeping this high-performance machine running smoothly for years to come. Its enduring appeal lies in its ability to blend luxury sedan comfort with genuine sports car performance, a combination that continues to make it a sought-after vehicle for driving enthusiasts.