The 2012 Infiniti G25, equipped with the naturally aspirated 2.5-liter VQ25HR V6 engine, is a sports sedan known for its smooth power delivery and agile handling. However, like any performance vehicle, its longevity and reliability depend heavily on the quality of fluids used during maintenance. The V6 engine operates at high temperatures and demands precise viscosity control to minimize wear on critical components like the VVEL (Variable Valve Event and Lift) system. Using the correct oil, filter, and other lubricants ensures the transmission shifts smoothly and the cooling system prevents overheating, keeping the car performing as intended by the manufacturer.
Recommended AMSOIL Products
- AMSOIL Signature Series 5W-30 100% Synthetic Motor Oil – The top choice for maximum protection, allowing for up to 25,000 miles of change intervals while offering 75% more protection against horsepower loss and wear.
- AMSOIL Extended-Life 5W-30 100% Synthetic Motor Oil – Ideal for drivers who want a balance of extended intervals and cleaning power, providing 20,000 miles of protection with 37% more cleaning ability.
- AMSOIL OE 5W-30 100% Synthetic Motor Oil – A premium synthetic option formulated to fight sludge and deposits, offering a cost-effective alternative that outperforms conventional oils while meeting OEM requirements.
- AMSOIL 5W-30 100% Synthetic High-Mileage Motor Oil – Specifically designed for engines with over 75,000 miles, featuring boosted detergents and seal conditioners to reduce sludge by 67% and control oil consumption.
- AMSOIL Oil Filter – Provides 99% filtration efficiency at 20 microns, offering lower restriction and greater capacity to reduce engine wear during extended intervals.
- WIX Oil Filter – A premium aftermarket filter option featuring improved media that outperforms standard OEM-branded filters for reliable engine protection.
Engine Oil and Filtration
For the 2.5-liter VQ25HR engine, the recommended oil viscosity is 5W-30. The engine requires 5.0 quarts of oil, including the filter replacement. After refilling, it is crucial to check the oil level and torque the drain plug to 25 ft/lbs, ensuring a new washer is installed on the drain bolt to prevent leaks. The V6 engine is sensitive to oil degradation, so using a high-performance synthetic motor oil can significantly reduce the risk of oil coking and sludge buildup, which are common issues in high-stress driving conditions.
The AMSOIL Signature Series 5W-30 100% Synthetic Motor Oil is the most robust option, delivering superior resistance to thermal breakdown and oxidation. This ensures the oil maintains its viscosity and protective properties even during long highway drives or cold winter starts. For owners who prefer slightly longer intervals but still want top-tier protection, the Extended-Life 5W-30 is an excellent alternative. It provides robust cleaning power to remove carbon deposits and prevent the formation of low-speed pre-ignition (LSPI), keeping the engine internals clean over time.
If your Infiniti G25 has accumulated significant mileage, the 5W-30 High-Mileage Motor Oil offers unique chemistry to address seal hardening and increased oil consumption. The enhanced anti-wear additives and reduced sludge formation help revitalize older engines, extending their operational life and improving overall performance. Pairing your oil choice with a high-quality filter is essential; the AMSOIL Oil Filter EA15K12 provides extended service life and greater contaminant capacity, while the WIX Oil Filter 51358 offers a premium alternative with superior media technology.
Transmission and Drivetrain Lubricants
The 2012 Infiniti G25 is equipped with a 7-speed automatic transmission (RE7R01A), which is a key component of the vehicle’s responsive driving dynamics. This transmission requires a fluid that can handle elevated temperatures and provide smooth shifts under varying loads. AMSOIL offers several transmission fluids specifically formulated for this application. The AMSOIL Signature Series Fuel-Efficient 100% Synthetic Automatic Transmission Fluid stands out for its ability to withstand heavy towing and challenging terrain while remaining fluid in sub-zero temperatures.
The OE Fuel-Efficient version provides a cost-effective solution that protects against wear and resists harmful sludge, promoting smooth, shudder-free shifts. For transfer cases, the AMSOIL Signature Series Multi-Vehicle 100% Synthetic Automatic Transmission Fluid can also be utilized if specified by the manufacturer, offering protection against heavy abuse and thermal runaway. The fill capacity for the 7-speed transmission is approximately 9.7 quarts for a total fill, though top-offs should be done cautiously based on the dipstick or level sensor.
Front and Rear Differential Lubes
While the G25 is a front-wheel-drive and all-wheel-drive sedan, understanding the differential requirements is vital for maintenance. The front differential (F160A) typically requires an 80W-90 synthetic gear lube, with a capacity of roughly 1.4 pints. The rear differential on all-wheel-drive models varies; with a 7-speed transmission, it requires 3 pints of 75W-90 synthetic lube, while rear-wheel-drive configurations without the 7-speed transmission use 80W-90. The AMSOIL SEVERE GEAR® 80W-90 and 75W-90 100% Synthetic Gear Lubes are engineered to provide advanced protection against wear and thermal runaway. These fluids contain friction modifiers for limited-slip applications and help reduce operating temperatures, ensuring long oil and seal life.
For those seeking maximum durability, the AMSOIL 75W-90 Long Life 100% Synthetic Gear Lube is a robust option, specifically engineered for extended service life and high-load protection. These gear lubes control thermal runaway effectively and protect against rust and corrosion, helping reduce operating temperatures and extending the life of the equipment. Always ensure that a new washer is installed on the drain and fill plugs, torquing them to the specified 26 ft/lbs to prevent leaks and maintain proper pressure.
Coolant and Brake Fluids
The cooling system is critical for the VQ25HR engine, which operates at optimal temperatures for performance. The coolant capacity varies depending on the drivetrain: AWD models require 9.3 quarts, while RWD models require 8.8 quarts. AMSOIL Passenger Car & Light Truck Antifreeze & Coolant is a unique poly-organic acid (OAT) formulation that protects all cooling system metals, gaskets, and hoses. It offers protection for up to 150,000 miles or 5 years, ensuring the engine stays cool even in extreme heat. For a concentrated option, the AMSOIL Propylene Glycol Antifreeze and Engine Coolant can be mixed to the desired ratio, offering protection for up to 150,000 miles or 5 years in passenger cars.
For the braking system, the G25 requires DOT 3 hydraulic brake fluid. The AMSOIL DOT 3 and DOT 4 100% Synthetic Brake Fluid provides excellent ABS and traction-control responsiveness with stable viscosity over a wide temperature range. This ensures consistent pedal feel and stopping power in both hot and cold conditions. Additionally, the AMSOIL 100% Synthetic Multi-Vehicle Power Steering Fluid is recommended to keep the power steering system quiet and responsive. It reduces friction and helps seals remain soft, preventing leaks and ensuring quiet operation for the vehicle’s steering system.
Seasonal and Additional Protection
Maintaining the Infiniti G25 involves more than just fluids; it requires comprehensive care. For storage periods, the AMSOIL Gasoline Stabilizer helps keep fuel fresh for up to 12 months, protecting against varnish and gum buildup. The AMSOIL Engine Fogging Oil is ideal for protecting internal components during long periods of inactivity. Owners can also use the AMSOIL P.i.® Performance Improver Gasoline Additive, which restores up to 14% horsepower and improves fuel economy by cleaning GDI fuel injectors. For those looking to restore the vehicle’s appearance, the AMSOIL Miracle Wash Waterless Wash and Wax Spray provides a fantastic shine and protective finish without the need for soap or water.
Why Owners Like This Vehicle
The 2012 Infiniti G25 holds a special place in the hearts of driving enthusiasts who appreciate the blend of luxury, performance, and engineering reliability. Based on the Nissan F-platform, the G25 shares its heart with the Nissan 370Z’s famous VQ series engine. The 2.5-liter V6 produces around 200 horsepower, delivering a linear and smooth power delivery that feels natural rather than aggressive. Unlike turbocharged rivals that might suffer from lag, the VQ25HR’s naturally aspirated design provides immediate throttle response, making it a joy to drive on winding roads.
The interior of the G25 is widely praised for its high-quality materials and ergonomic design, offering a driver-focused cockpit with supportive seats and intuitive controls. Infiniti’s reputation for build quality is evident in the G25, with a solid chassis that balances sporty handling with a comfortable ride. The availability of all-wheel drive in certain trims made it a versatile choice for year-round driving in various climates, adding extra confidence without sacrificing the agile handling character the G25 is known for. Its design, which marked a departure from the angular lines of its predecessors to a more fluid and elegant aesthetic, has aged remarkably well, maintaining its appeal as a sophisticated sports sedan.