The 2018 Lexus NX300h is a compact luxury crossover hybrid that pairs a 2.5-liter four-cylinder engine with an electric motor for an efficient and smooth driving experience. Because this vehicle relies on the 2AR-FXE engine code, it requires lubricants specifically engineered to meet the stringent demands of modern hybrid powertrains. Proper fluid maintenance is critical for preserving fuel economy, reducing wear on the high-speed electric motor components, and ensuring the internal combustion engine remains free of sludge and deposits over the long term. Using the correct viscosity and formulation can extend service intervals and keep the vehicle operating at peak performance.
Recommended AMSOIL Products
- AMSOIL Signature Series 0W-20 100% Synthetic Motor Oil – Provides the highest level of protection with guaranteed performance for up to 25,000 miles, ensuring superior horsepower retention and reduced wear in the NX300h’s hybrid engine.
- AMSOIL 0W-20 100% Synthetic Hybrid Motor Oil – Specifically formulated for hybrid applications to offer unique protection against sludge and maximize the fuel efficiency benefits of the NX300h’s electric assist system.
- AMSOIL Extended-Life 0W-20 100% Synthetic Motor Oil – Offers a balanced approach with extended service intervals of up to 20,000 miles and enhanced cleaning power to keep the engine running smoothly.
- AMSOIL OE 0W-20 100% Synthetic Motor Oil – An excellent value option that outperforms conventional oils and meets OEM mileage standards with reliable sludge and deposit control.
- AMSOIL 0W-20 100% Synthetic High-Mileage Motor Oil – Designed for engines with over 75,000 miles, featuring a boosted detergent package and reduced sludge to help extend the life of older vehicles.
- AMSOIL Oil Filter – Features 99% filtration efficiency at 20 microns and greater capacity for contaminants, ensuring maximum engine protection and oil flow.
- AMSOIL Passenger Car & Light Truck Antifreeze & Coolant – A pre-mixed ethylene glycol formulation that exceeds OEM requirements and protects the cooling system for up to 150,000 miles or 5 years.
- AMSOIL Signature Series Fuel-Efficient 100% Synthetic Automatic Transmission Fluid – Withstands severe driving conditions, high temperatures, and ensures fluidity in sub-zero temperatures for the NX300h’s hybrid transmission system.
- AMSOIL DOT 3 and DOT 4 100% Synthetic Brake Fluid – Delivers excellent ABS responsiveness and a stable viscosity range, providing safe braking performance regardless of weather conditions.
When selecting a motor oil for the 2018 Lexus NX300h, the primary requirement is a 0W-20 viscosity grade. This low-viscosity synthetic oil is essential for optimal fuel economy and cold-weather starting, which are critical factors for a hybrid vehicle where the engine frequently cycles on and off. The engine capacity is 4.6 quarts when changing the filter. It is important to use the correct oil viscosity at every oil change; while AMSOIL oils can extend intervals, the viscosity specification remains the manufacturer’s baseline for proper lubrication. The AMSOIL Oil Filter (EA15K02-EA) is the ideal companion for any AMSOIL motor oil, featuring a bypass valve and high-capacity media that traps smaller particles than traditional filters. For vehicle owners with over 75,000 miles, the High-Mileage variant offers unique additives to condition seals and reduce consumption. If you prefer an alternative filter, the WIX Oil Filter is also a suitable option that offers premium media improvements over standard equipment manufacturer filters.
Transmission and Cooling Fluids
The transmission in the NX300h requires specific attention due to the unique load characteristics of a hybrid powertrain. The automatic transmission fluid capacity for a total fill is 4 quarts. AMSOIL offers two primary choices for this application: the Signature Series Fuel-Efficient 100% Synthetic Automatic Transmission Fluid and the OE Fuel-Efficient 100% Synthetic Automatic Transmission Fluid. Both are designed to protect against wear, sludge, and temperature-related problems. The Signature Series version is particularly effective for vehicles subject to heavy towing or challenging terrain, while the OE version provides reliable protection that meets or exceeds original specifications at a competitive value. Maintaining clean transmission fluid ensures smooth shifting and reduces the likelihood of costly internal repairs.
Coolant management is equally vital for the NX300h, which features an inverter cooling system. The capacity for the inverter system is 3.3 quarts, while the main engine cooling system requires between 7.1 and 7.7 quarts depending on the specific configuration. AMSOIL Passenger Car & Light Truck Antifreeze & Coolant is a phosphate-, nitrite-, and silicate-free formulation that offers 150,000 miles of protection. For those who prefer a concentrated option, the Propylene Glycol Antifreeze and Engine Coolant allows for flexible mixing ratios and offers extended service life up to 150,000 miles or 5 years. Both formulations protect all cooling system metals, gaskets, and hoses from corrosion, ensuring the hybrid components and engine remain at optimal operating temperatures.
Essential Additional Fluids and Maintenance
Beyond oil and transmission fluid, the NX300h benefits from high-quality brake fluid to maintain safe stopping power. The recommended fluid is AMSOIL DOT 3 and DOT 4 100% Synthetic Brake Fluid. This fluid provides superior stability over a wide temperature range compared to conventional glycol-based fluids, ensuring consistent pedal feel and ABS responsiveness. For owners who store their vehicles seasonally or plan to keep them for extended periods without driving, AMSOIL Gasoline Stabilizer is recommended to keep fuel fresh for up to 12 months. Additionally, AMSOIL Engine Fogging Oil can be used to protect internal engine components from rust during long periods of inactivity.
To further enhance performance and fuel economy, AMSOIL P.i.® Performance Improver Gasoline Additive is highly effective. This additive restores GDI fuel injectors to 100% flow rate after just one tank of fuel, helping to prevent carbon buildup which is common in direct injection engines. It can also help reduce the need for higher-octane fuel and maintains engine cleanliness. For cabin air quality, the Wix Cabin Air Filter is available to trap dust, pollen, and other airborne contaminants, ensuring a clean environment for passengers.
Why Owners Like This Vehicle
The 2018 Lexus NX300h has established itself as a standout in the compact luxury crossover segment, offering a blend of premium craftsmanship and innovative hybrid technology. Derived from the Toyota RAV4 platform but tuned with the distinct Lexus signature of silence and refinement, this vehicle appeals to drivers who prioritize fuel efficiency without sacrificing the luxury features expected from a Japanese automaker. The powertrain, featuring the 2AR-FXE engine paired with an electric motor, delivers a seamless driving experience where the transition between electric-only driving and gasoline propulsion is virtually imperceptible. This makes the NX300h an ideal choice for city commuters and suburban families looking to minimize their carbon footprint while enjoying a comfortable, quiet ride.
Owners often cite the intuitive handling and composed ride quality as major selling points. The independent suspension tuning on the NX300h provides a balance between comfort and agility, making it suitable for both daily commutes and weekend getaways. The interior design reflects Lexus’s commitment to “Takumi” craftsmanship, utilizing high-quality materials, precise fit-and-finish, and ergonomic controls that reduce driver fatigue. The infotainment system, while not the most cutting-edge by modern smartphone standards, is robust and reliable, offering a user-friendly interface that is simple to operate while driving.
Like any complex machine, the NX300h does have specific maintenance considerations that can benefit from high-quality synthetic lubricants. One common issue observed in this generation of Lexus hybrids is the potential for sludge buildup in the engine if conventional oil or extended intervals between changes are not managed carefully. The frequent start-stop nature of the hybrid system can lead to increased fuel dilution in the oil, which can degrade the lubricant’s viscosity and protective properties over time. Using a synthetic oil with superior stability and detergent packages helps neutralize this acid and dilution, preserving engine life.
Another area of concern for owners involves the cooling system. The NX300h’s hybrid inverter requires a dedicated cooling loop, and any failure to maintain proper coolant levels or quality can lead to overheating of sensitive electronics. Ensuring the coolant is refreshed regularly with a high-grade antifreeze can prevent corrosion and scaling that might otherwise compromise the cooling efficiency. Additionally, the high-voltage battery system in the NX300h relies on a cooling loop that must remain free of debris and corrosion to ensure the battery’s longevity and performance. Proper maintenance of the engine and cooling fluids is not just about keeping the engine running; it is about protecting the expensive hybrid components that make this vehicle unique. By adhering to the recommended fluid specifications and using premium synthetic products, owners can mitigate these risks and keep their luxury crossover running smoothly for years to come.