The 2009 Audi S4 equipped with the 4.2L V8 engine (engine code BHF B) is a vehicle that demands precision maintenance. This high-performance sedan features a naturally aspirated powerplant designed to deliver responsive power and smooth operation. To maintain the engineering integrity of this German vehicle, owners must rely on fluids that meet stringent OEM specifications. Using the correct lubricants ensures optimal thermal management, reduces engine wear, and preserves the performance characteristics that make this model a favorite among enthusiasts.
Recommended AMSOIL Products
For the engine, the 2009 Audi S4 requires a synthetic oil that meets specific Audi and Volkswagen quality standards. The recommended viscosity range includes 5W-40, 5W-30, 0W-40, and 0W-30, depending on the climate and operating conditions. The total capacity for an oil change with a filter is 9.3 quarts. For the cooling system, the radiator holds 12.9 quarts of antifreeze. The automatic transmission, specifically the 09L type, requires a total fill of 10.4 quarts, while the manual transmission (0A3) holds 6.8 pints. The transfer case and differential units also have specific fill requirements that necessitate premium gear lubricants.
- AMSOIL 5W-40 MS 100% Synthetic European Motor Oil – Designed specifically for the unique demands of European gasoline, diesel, and hybrid vehicles, this oil features a precise blend of synthetic base oils and premium additives to protect the 4.2L engine.
- AMSOIL 5W-40 FS 100% Synthetic European Motor Oil – A high-performance synthetic option formulated to meet strict European quality standards, offering excellent protection against wear and thermal breakdown.
- AMSOIL 0W-40 FS 100% Synthetic European Motor Oil – Ideal for extreme temperature conditions, this fluid ensures rapid lubrication at startup and maintains viscosity stability under high heat.
- MANN-FILTERS Oil Filter – Offers premium media that improves upon original equipment manufacturer filters, ensuring maximum oil flow and contaminant capture for your Audi S4.
- AMSOIL Passenger Car & Light Truck Antifreeze & Coolant – A 50/50 pre-mix formulation that protects all cooling system metals, gaskets, and hoses for up to 150,000 miles or 5 years.
- AMSOIL Propylene Glycol Antifreeze and Engine Coolant – A concentrated antifreeze that requires mixing with distilled water, offering extended protection up to 150,000 miles or 5 years in passenger cars.
- AMSOIL Signature Series Fuel-Efficient 100% Synthetic Automatic Transmission Fluid – Engineered to withstand heavy towing, elevated temperatures, and challenging terrain while remaining fluid in sub-zero conditions.
- AMSOIL OE Fuel-Efficient 100% Synthetic Automatic Transmission Fluid – Provides strong protection against wear for the 6-speed automatic transmission, matching original equipment requirements.
- AMSOIL 75W-90 Manual Transmission & Transaxle Gear Lube – Protects against increased heat and pressure with outstanding cold-flow properties and excellent compatibility with brass synchronizers.
- 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.
- AMSOIL 75W-90 Long Life 100% Synthetic Gear Lube – Specifically engineered for extended service life, providing high-load gear and bearing protection while improving cold-weather shifting.
- AMSOIL 100% Synthetic Multi-Vehicle Power Steering Fluid – Reduces friction and helps seals remain soft to prevent leaks, resisting heat for long fluid life.
Why Proper Lubrication Matters for the 4.2L Engine
The 4.2L V8 in the 2009 Audi S4 is a sophisticated powerplant that operates at higher thermal loads compared to standard sedans. Proper lubrication is not merely about keeping the engine running; it is about preserving the precise tolerances required for peak performance. The engine oil must meet specific Audi and Volkswagen quality standards to ensure compatibility with the engine’s materials and seals. Without the correct fluid, owners may experience reduced fuel economy, increased emissions, or accelerated component wear.
The oil capacity for the 2009 Audi S4 is 9.3 quarts when the filter is included. It is crucial to use a torque of 47 ft/lbs on the oil drain plug during installation to prevent leaks or stripping. After refilling, the oil level must be checked to ensure it falls within the proper operating range. If the recommended synthetic oil meeting the specific Audi standard is not available in your area, a viscosity grade suitable for the local climate and operating conditions should be used as a temporary measure until the correct fluid can be sourced.
Similarly, the cooling system requires careful attention. The 2009 Audi S4 holds 12.9 quarts of coolant. Using a high-quality antifreeze and coolant mixture prevents corrosion, boiling, and freezing. AMSOIL formulations are designed to exceed original equipment manufacturer requirements, protecting the aluminum components and gaskets typical of this engine family. The antifreeze should be compatible with the cooling system metals and hoses, and phosphate-, nitrate-, nitrite-, silicate-, borate-, and amine-free formulations are available to ensure long-term compatibility.
Transmission and Drivetrain Protection
The 2009 Audi S4 comes with various transmission configurations, including a 6-speed automatic (09L) and manual options (0A3). The automatic transmission requires a total fill of 10.4 quarts, while the initial fill capacity is 11 quarts. The manual transmission holds 6.8 pints. The 0A3 manual transmission and transfer case (Center DIFF) require specific gear lubes. The transfer case capacity is 1.1 pints, and the front differential holds 2.3 pints, while the rear differential also holds 2.3 pints.
Using a synthetic gear lube like the 75W-90 formula provides outstanding protection against the heat and pressure generated during spirited driving. These lubricants inhibit rust and corrosion and offer excellent seal compatibility. For the automatic transmission, the fluid must remain fluid in sub-zero temperatures and withstand the rigors of elevated temperatures. The manual transmission fill plug torque is 33 ft/lbs, and the oil drain plug torque is 47 ft/lbs. Ensuring the correct fill levels and using the specified synthetic fluids will extend the life of the transmission and differential components.
Brake Fluid and Power Steering
The braking system in the Audi S4 utilizes hydraulic brake fluid that meets DOT 4 specifications. AMSOIL’s 100% synthetic brake fluid provides a stable viscosity over a wide temperature range, ensuring excellent ABS and traction-control responsiveness. This stability is critical for maintaining consistent pedal feel and stopping power in both cold winter mornings and hot summer days.
The power steering system also benefits from synthetic fluid designed for quiet operation. The fluid resists heat for long life and reduces friction within the system. It contains strong anti-wear protection and helps seals remain soft to prevent leaks. Using a fluid like the 100% Synthetic Multi-Vehicle Power Steering Fluid ensures the steering rack operates smoothly and extends the service life of the steering components.
For those who store their vehicles seasonally, additives like AMSOIL Gasoline Stabilizer can help keep fuel fresh for up to 12 months, protecting against varnish and gum buildup. Additionally, AMSOIL Engine Fogging Oil is an effective rust preventive for internal engine components during long periods of inactivity.
About the 2009 Audi S4
The 2009 Audi S4 represents a significant point in the lineage of Audi’s performance sedan lineup. Part of the B7 chassis generation, this vehicle is powered by a robust 4.2-liter naturally aspirated V8 engine, code BHF B. This engine is renowned for its smooth power delivery and linear acceleration, offering a driving experience that prioritizes refinement and torque over the high-revving, turbocharged characteristics of later models. The S4 was positioned as a “quattro” sedan, meaning it featured Audi’s legendary permanent all-wheel-drive system, providing exceptional traction and handling in various weather conditions.
Inside the cabin, the 2009 S4 blends luxury with sportiness, featuring high-quality materials, supportive seats, and a driver-focused cockpit. It occupies a unique space in the market as a vehicle that is comfortable enough for daily commuting yet capable of spirited performance on the open road. The S4 shares its platform and many mechanical components with the A4, but the S4’s distinct engine, suspension tuning, and aggressive styling cues set it apart. Owners of this vehicle often appreciate the balance of German engineering, reliability, and the sheer presence of a V8-powered sedan from the late 2000s.
The B7 generation S4 is highly regarded by enthusiasts for its mechanical simplicity compared to the turbocharged models that followed. The naturally aspirated engine allows for a more predictable power curve and a distinct exhaust note that many fans prefer. As a result, keeping the vehicle in top condition with premium lubricants is a popular pursuit among owners who value longevity and performance.
Additional Maintenance Products
Beyond the essential fluids and filters, there are several products that can enhance the performance and maintenance of the 2009 Audi S4. AMSOIL P.i. Performance Improver is a gasoline additive that can restore up to 14% horsepower and clean fuel injectors, helping the engine run more efficiently. For upper cylinder lubrication and corrosion inhibition, AMSOIL offers a specialized product that works with capless fuel systems. General maintenance can be supported by AMSOIL Synthetic Multi-Purpose Grease for chassis components, which resists thermal and oxidation degradation.
Protective coatings like the AMSOIL Heavy-Duty Metal Protector can help guard the undercarriage against salt and moisture corrosion, while the MP Metal Protector can help free rusted components. For cleaning, products like the AMSOIL Brake and Parts Cleaner ensure that brake components are free of oil and grease without leaving residue. The AMSOIL Engine Degreaser is effective for removing the toughest grease from engine surfaces, and the High-Foam Car Shampoo provides a safe way to wash the exterior without damaging paint or coatings.
For vehicle owners who want to keep their 2009 Audi S4 in peak condition, utilizing the recommended AMSOIL lubricants and additives ensures that every aspect of the vehicle is protected. From the engine oil meeting strict European standards to the gear lube that withstands high loads, these products are designed to deliver maximum performance and longevity.