The 2009 Infiniti QX56 is a formidable full-size SUV built on a robust platform, but like any complex machine with a large displacement engine, it demands precise lubrication to maintain its performance and longevity. Operating the 5.6L V8 (Engine Code VK56DE R) places significant stress on the drivetrain, especially when towing or driving in extreme temperatures. Proper fluid maintenance is not just about following a schedule; it is about selecting the right chemistry to combat wear, sludge, and heat. By using high-quality synthetic lubricants, owners can ensure that every component, from the pistons to the transfer case, receives the protection it needs to handle heavy loads and long commutes without compromise.
Recommended AMSOIL Products
- AMSOIL Signature Series 5W-30 100% Synthetic Motor Oil – Engineered for maximum engine protection and capable of up to 25,000 miles of service between changes, offering superior wear resistance for the VK56DE engine.
- AMSOIL Extended-Life 5W-30 100% Synthetic Motor Oil – Provides extended protection for up to 20,000 miles with enhanced cleaning power to help keep the engine running smoother for a longer duration.
- AMSOIL OE 5W-30 100% Synthetic Motor Oil – A cost-effective synthetic option designed to fight sludge and deposits while outperforming conventional oils for standard vehicle maintenance.
- AMSOIL 5W-30 100% Synthetic High-Mileage Motor Oil – Specifically formulated for engines with over 75,000 miles to reduce leaks and sludge while maintaining performance.
- AMSOIL Oil Filter – Features 99% efficiency at 20 microns and higher capacity for contaminants compared to standard filters, ensuring the oil stays clean longer.
- WIX Oil Filter – A premium aftermarket alternative with advanced media that offers improvements over original equipment manufacturer-branded filters.
- AMSOIL Passenger Car & Light Truck Antifreeze & Coolant – A pre-mixed 50/50 solution that provides corrosion protection for up to 150,000 miles, compatible with all cooling system metals and hoses.
- AMSOIL Propylene Glycol Antifreeze and Engine Coolant – A concentrated formula offering extended protection up to 150,000 miles or 5 years, ideal for maintaining optimal operating temperatures in the heavy-duty cooling system.
- AMSOIL Signature Series Fuel-Efficient 100% Synthetic Automatic Transmission Fluid – Withstands heavy towing and high temperatures while remaining fluid in sub-zero conditions for the 5-speed RE5R05A transmission.
- AMSOIL OE Fuel-Efficient 100% Synthetic Automatic Transmission Fluid – A cost-effective option that protects against wear and promotes smooth, shudder-free shifts for automatic transmissions.
- AMSOIL SEVERE GEAR® 75W-90 100% Synthetic Gear Lube – Essential for the front and rear differentials, providing advanced protection against wear and thermal runaway while controlling operating temperatures.
- AMSOIL 75W-90 Long Life 100% Synthetic Gear Lube – An extended-drain option designed for long-lasting protection in heavy-load applications.
- AMSOIL DOT 3 and DOT 4 100% Synthetic Brake Fluid – Delivers excellent ABS and traction-control responsiveness with stable viscosity across a wide temperature range.
- AMSOIL 100% Synthetic Multi-Vehicle Power Steering Fluid – Reduces friction and helps keep seals soft to prevent leaks, ensuring quiet operation and high-temperature protection.
When performing maintenance on the QX56, the engine oil capacity is a critical figure to note. With a standard oil filter installed, the 5.6L VK56DE R engine requires 6.6 quarts of oil. After refilling, it is essential to check the oil level to ensure proper lubrication. The drain plug torque specification is 25 ft/lbs, which helps prevent leaks without damaging the oil pan. Proper filtration is equally important; the AMSOIL Oil Filter is designed to offer superior capacity for contaminants, helping to reduce engine wear significantly compared to standard filters. For those who prefer an aftermarket option, the WIX Oil Filter offers premium media that outperforms many OEM-branded filters, ensuring that the critical engine components remain free of abrasive particles.
The cooling system for this massive SUV is equally demanding. The radiator and cooling system hold approximately 15.2 quarts of fluid. Owners have two excellent synthetic AMSOIL Passenger Car & Light Truck Antifreeze & Coolant options depending on their preference for convenience or performance. This antifreeze & coolant comes as a convenient 50/50 pre-mix, ready to use and formulated to protect all cooling system metals, gaskets, and hoses for up to 150,000 miles. Alternatively, the AMSOIL Propylene Glycol Antifreeze and Engine Coolant is a concentrated option that offers the same impressive service intervals and protection levels. This concentrate requires mixing with distilled or high-quality water and is ideal for those who want a highly customizable solution that greatly surpasses standards for metallic corrosion and erosion.
Beyond the engine and cooling system, the QX56’s drivetrain requires specialized attention. The automatic transmission, specifically the 5-speed RE5R05A unit, requires a full fill of 11.2 quarts to replace the fluid entirely. Using a synthetic AMSOIL Signature Series Fuel-Efficient 100% Synthetic Automatic Transmission Fluid is vital for a vehicle that often hauls trailers or carries heavy loads. This ATF withstands the rigors of heavy towing and elevated temperatures while remaining fluid in sub-zero conditions. For those seeking a more economical option that still delivers synthetic performance, the AMSOIL OE Fuel-Efficient Automatic Transmission Fluid protects against wear and resists harmful sludge, promoting smooth shifts.
The differential and transfer case lubrication is another area where synthetics shine. The front differential requires 3.4 pints of fluid, while the rear differential requires 3.7 pints. The transfer case lubricant capacity varies depending on the specific setup, but generally requires a specific volume to ensure smooth power distribution. AMSOIL SEVERE GEAR® 75W-90 100% Synthetic Gear Lube is the recommended synthetic gear lube for these differentials. It provides advanced protection against wear, controls thermal runaway, and contains friction modifiers for limited-slip applications. This oil helps reduce operating temperatures and extends the life of seals and equipment. For those looking for maximum service intervals, the AMSOIL 75W-90 Long Life 100% Synthetic Gear Lube offers up to 500,000 miles of protection in heavy applications. Additionally, the AMSOIL SEVERE GEAR® 80W-90 and 75W-110 are available for specific temperature requirements or gear ratios.
Maintenance also extends to the braking and steering systems. For the hydraulic AMSOIL DOT 3 and DOT 4 100% Synthetic Brake Fluid is the top recommendation. It ensures excellent responsiveness for ABS and traction control systems by maintaining a stable viscosity over a wide temperature range. For power steering, the AMSOIL 100% Synthetic Multi-Vehicle Power Steering Fluid helps reduce friction and prevents seal hardening, which is crucial for maintaining quiet operation and preventing leaks in the aging seals of a 2009 model.
Model History and Performance
The 2009 Infiniti QX56 represents the pinnacle of luxury utility vehicles from Nissan’s premium division during that era. Based on the same rugged platform as the Nissan Armada, the QX56 was designed for owners who required the substantial towing capability of a truck with the plush interior appointments of a high-end sedan. Under the hood, the 5.6-liter V8 engine, known internally as the VK56DE, was a powerhouse of reliability and smooth power delivery, producing significant horsepower and torque figures that made it a favorite for families needing to haul large trailers or carry passengers in comfort.
This model year continued the legacy of Infiniti’s large SUVs, which positioned themselves as direct competitors to the Mercedes-Benz GL-Class and the Cadillac Escalade. The QX56 was renowned for its spacious interior, offering ample room for seven passengers and a versatile cargo area that could accommodate significant loads. The suspension was tuned to provide a comfortable ride even when the vehicle was fully loaded, absorbing road imperfections effectively. Its all-wheel-drive system, when equipped, provided excellent traction in various weather conditions, making it a reliable choice for drivers in regions with harsh winters or unpredictable terrain.
From a mechanical standpoint, the QX56 is built to last. The transmission and drivetrain components are robust, capable of handling the torque produced by the large engine. However, this robustness means that when maintenance is performed, the capacity for fluids is substantial, and the longevity of the vehicle relies heavily on the quality of those fluids. By maintaining the QX56 with premium synthetics, owners can extend the life of these expensive components and ensure that the vehicle continues to perform with the smoothness and power that Infiniti enthusiasts expect. The combination of high-performance lubricants and the vehicle’s solid engineering foundation results in a driving experience that is both luxurious and dependable.