Maintaining the 2009 Infiniti M45 with the 4.5-liter VK45DE engine requires more than just a standard oil change; it demands a comprehensive approach to lubrication that addresses the high-performance nature of this luxury sedan. Proper fluid selection ensures optimal thermal stability, reduces friction in the V8 powerplant, and extends the service intervals for the transmission and cooling systems. By utilizing specific synthetic formulations designed for this vehicle’s requirements, owners can maintain peak performance and protect against wear, even under severe driving conditions.
Recommended AMSOIL Products
- AMSOIL Signature Series 5W-30 100% Synthetic Motor Oil – Provides unsurpassed engine protection against wear and horsepower loss, offering up to 25,000 miles of coverage.
- AMSOIL Extended-Life 5W-30 100% Synthetic Motor Oil – Delivers extended protection up to 20,000 miles with enhanced cleaning power to keep the engine running smoothly.
- AMSOIL OE 5W-30 100% Synthetic Motor Oil – A cost-effective alternative that fights sludge and deposits while meeting OEM mileage expectations.
- AMSOIL 5W-30 100% Synthetic High-Mileage Motor Oil – Formulated specifically for vehicles with over 75,000 miles, featuring boosted detergents to clean internal components.
- AMSOIL Oil Filter – Engineered for 99% filtration efficiency at 20 microns to capture small contaminants and reduce engine wear.
- WIX Oil Filter – Offers premium media with performance improvements over original equipment manufacturer branded filters.
- AMSOIL Signature Series Fuel-Efficient 100% Synthetic Automatic Transmission Fluid – Withstands heavy towing and elevated temperatures while remaining fluid in sub-zero conditions.
- AMSOIL OE Fuel-Efficient 100% Synthetic Automatic Transmission Fluid – Protects against wear and promotes smooth, shudder-free shifts in the 5-speed transmission.
- AMSOIL Passenger Car & Light Truck Antifreeze & Coolant – A 50/50 pre-mix formulation that protects cooling system metals and hoses up to 150,000 miles.
- AMSOIL SEVERE GEAR® 75W-90 100% Synthetic Gear Lube – Advanced protection for front and rear differentials, controlling thermal runaway and reducing operating temperatures.
- AMSOIL DOT 3 and DOT 4 100% Synthetic Brake Fluid – Ensures excellent ABS and traction-control responsiveness with a stable viscosity across a wide temperature range.
- AMSOIL 100% Synthetic Multi-Vehicle Power Steering Fluid – Reduces friction and helps seals remain soft to prevent leaks while providing excellent high-temperature protection.
Engine Oil and Filtration Requirements
The heart of the 2009 Infiniti M45 is the 4.5-liter VK45DE V8 engine. This powerplant delivers significant horsepower and torque, generating substantial heat and stress on lubricants. To maintain its performance envelope, the engine requires a high-quality synthetic motor oil capable of withstanding extreme temperatures without breaking down. The recommended viscosity grade for this engine is 5W-30, which flows easily during cold starts to provide immediate protection while maintaining a robust film thickness at operating temperatures.
For the 2009 M45, the oil capacity varies slightly depending on the specific service procedure, but the standard total fill with a filter change is approximately 6.1 quarts. However, some service data indicates a refill capacity of 5.8 quarts with a filter change. It is crucial to fill the system to the specified level and verify the oil level on the dipstick after refilling. The oil drain plug should be torqued to 25 ft/lbs to ensure a secure seal without damaging the threads.
Selecting the right motor oil allows owners to extend service intervals significantly compared to conventional oils. The Signature Series offers the longest protection, rated for up to 25,000 miles or one year, making it an ideal choice for those who want to maximize the time between maintenance visits. For vehicles with higher mileage, the High-Mileage variant includes enhanced additives designed to condition seals and reduce sludge buildup, helping older engines run smoother. Additionally, the OE option provides a solid balance of performance and value, effectively fighting deposits while meeting standard industry requirements.
Complementing the synthetic oil is the filtration system. The AMSOIL Oil Filter is a high-capacity filter designed to trap wear-causing contaminants more effectively than many competitors. It features greater capacity for small particles and maintains lower restriction, ensuring that oil flow remains unrestricted even under heavy loads. For those who prefer a well-known aftermarket brand, the WIX Oil Filter is also compatible, offering premium media that improves upon original equipment standards.
Transmission and Transfer Case Lubrication
The 2009 Infiniti M45 is equipped with an automatic transmission, specifically the RE5R05A 5-speed unit found in models with the rear-wheel-drive configuration. Maintaining this transmission is critical for smooth shifting and longevity. The automatic transmission fluid (ATF) in this vehicle faces the rigors of heavy towing, elevated temperatures, and challenging terrain, particularly in the V8 models. AMSOIL offers both Signature Series and OE formulations of fuel-efficient synthetic ATFs that are designed to withstand these conditions.
The total fill capacity for the automatic transmission is approximately 10.9 quarts for a complete flush, though standard service intervals will require significantly less fluid. The AMSOIL Signature Series ATF is rated to remain fluid in sub-zero temperatures and provides reserve protection during heavy use, ensuring consistent performance. The OE Fuel-Efficient variant also offers strong protection against wear and resistance to sludge, promoting shudder-free shifts. These synthetic fluids are engineered to reduce friction, which can contribute to improved fuel economy and reduced operating temperatures within the transmission.
While the Infiniti M45 is primarily a rear-wheel-drive sedan, it is worth noting the lubrication needs for any differential or transfer case components if the vehicle has been modified or if it is a specific all-wheel-drive variant. For standard applications, the rear differential requires a GL-5 rated gear lube. The capacity for the rear differential is approximately 3 pints, while the front differential (if equipped) holds about 1.4 pints. For these components, AMSOIL SEVERE GEAR® 75W-90 100% Synthetic Gear Lube is an excellent choice. This product contains friction modifiers suitable for limited-slip applications and helps reduce operating temperatures, extending the life of the gears and seals.
Cooling System and Brake Fluids
A robust cooling system is essential for the 4.5-liter V8 to prevent overheating, especially during aggressive driving or towing. The cooling system capacity for the 2009 M45 is approximately 11 quarts. AMSOIL Passenger Car & Light Truck Antifreeze & Coolant is a ready-to-use 50/50 pre-mix that provides protection against corrosion for all cooling system metals, gaskets, and hoses. It is phosphate, nitrite, and silicate-free, ensuring compatibility with all cooling system components and preventing the buildup of harmful deposits. For those who prefer a concentrated fluid, the Propylene Glycol Antifreeze and Engine Coolant offers a high-performance alternative that can be mixed with distilled water to achieve the desired freeze and boil-over protection.
Brake fluid integrity is paramount for safety. The 2009 Infiniti M45 requires a DOT 3 or DOT 4 hydraulic brake fluid. AMSOIL DOT 3 and DOT 4 100% Synthetic Brake Fluid provides a stable viscosity over a wide temperature range, which is critical for maintaining consistent brake pedal feel and responsiveness. This fluid is particularly beneficial for vehicles equipped with advanced ABS and traction-control systems, as it ensures rapid hydraulic response and prevents brake fade during heavy braking.
Power steering fluid is another often-overlooked fluid in luxury sedans. The M45 utilizes a power steering system that can benefit from synthetic lubricants. AMSOIL 100% Synthetic Multi-Vehicle Power Steering Fluid is formulated to reduce friction and prevent leaks by keeping seals soft. It resists heat and provides excellent anti-wear protection, ensuring quiet operation and long fluid life.
Vehicle Background and Performance History
The 2009 Infiniti M45 stands as a testament to the engineering prowess of Nissan’s luxury division during the late 2000s. As part of the M-series, the M45 was designed to compete directly with established European rivals like the BMW 5 Series and Mercedes-Benz E-Class. What sets the M45 apart in the enthusiast community is its powertrain: the VK45DE V8 engine, a direct successor to the legendary Nissan VQ series V8s known for their smoothness and high-revving capabilities.
This specific iteration of the M45 featured a 4.5-liter naturally aspirated V8 that produced substantial power, offering a driving experience that was both refined and spirited. The sedan’s platform provided a sophisticated suspension setup that balanced comfort with handling precision, making it a favorite among drivers who appreciated a “grand tourer” character. Unlike many of its contemporaries that were transitioning exclusively to turbocharged engines or smaller displacement V6s, the M45 retained a large, naturally aspirated V8, appealing to purists who valued linear power delivery and engine sound.
Owners of the 2009 M45 often cite its build quality and interior luxury as standout features. The cabin was equipped with high-quality materials and advanced technology for its time, creating a serene environment for long highway cruises or spirited back-road driving. The vehicle’s reputation for reliability, when properly maintained with high-quality synthetic fluids, has been well-documented, allowing it to rack up significant mileage without major mechanical issues. The 2009 model year represents a peak in the V8 sedan segment, offering a compelling blend of performance, luxury, and reliability that continues to attract loyal fans in the used car market today.
Maintenance and Fluid Selection Guide
Proper maintenance of the 2009 Infiniti M45 extends beyond just changing the engine oil. A holistic approach involves selecting the correct fluids for every component of the vehicle. For example, the use of AMSOIL’s synthetic gear lube in the differential ensures that the metal gears are protected from wear and corrosion, which is vital for a high-torque vehicle like the M45. Similarly, using a synthetic brake fluid like the DOT 3/DOT 4 blend ensures that the braking system remains responsive and safe, regardless of the weather conditions.
For owners looking to preserve the value of their vehicle, using fuel additives such as the AMSOIL P.i. Performance Improver Gasoline Additive can help restore up to 14% of horsepower and clean fuel injectors. This is particularly useful for older engines that may have accumulated carbon deposits over time. Additionally, for seasonal storage, products like the AMSOIL Gasoline Stabilizer can help keep fuel fresh for up to 12 months, preventing varnish and gum buildup in the fuel system.
By adhering to these fluid recommendations and utilizing high-quality synthetic products, Infiniti M45 owners can ensure that their vehicle remains in peak condition. Whether it is protecting the V8 engine from wear, ensuring smooth transmission shifts, or maintaining optimal braking performance, the right fluids make all the difference. The combination of advanced synthetic chemistry and precise application to the vehicle’s specific needs provides a comprehensive solution for maintaining this prestigious luxury sedan.