The 2018 Lexus RX350L is a sophisticated three-row luxury crossover that demands precision maintenance to sustain its performance and reliability. Powered by the 3.5-liter 2GR-FKS V-6 engine, this vehicle relies on high-quality lubricants to manage heat, reduce friction, and ensure smooth operation across varying driving conditions. Using the correct fluids not only extends the life of critical components but also preserves the vehicle’s fuel economy and power delivery. Proper lubrication is the foundation of long-term ownership, ensuring that the engine, transmission, and auxiliary systems remain protected against wear, sludge, and extreme temperatures.
Recommended AMSOIL Products
- AMSOIL Signature Series 0W-20 100% Synthetic Motor Oil – Offers unsurpassed engine protection and is ideal for vehicles seeking maximum performance and extended drain intervals.
- AMSOIL Extended-Life 0W-20 100% Synthetic Motor Oil – Provides up to 20,000 miles of protection and features 37% more cleaning power to keep the engine running smoother.
- AMSOIL OE 0W-20 100% Synthetic Motor Oil – A cost-effective choice that outperforms conventional oils while offering 100% synthetic protection for standard service intervals.
- AMSOIL 0W-20 100% Synthetic High-Mileage Motor Oil – Specifically formulated for engines with over 75,000 miles to reduce sludge and protect seals.
- AMSOIL Oil Filter – Delivers 99% filtering efficiency at 20 microns and allows lower restriction to keep engine parts lubricated effectively.
- WIX Oil Filter – Features premium media that offers improvements over original equipment manufacturer-branded filters.
- WIX Air Filter – Premium media ensures optimal airflow and filtration for the engine.
- AMSOIL Passenger Car & Light Truck Antifreeze & Coolant – A unique OAT formulation that protects cooling system metals, gaskets, and hoses for up to 150,000 miles.
- AMSOIL Propylene Glycol Antifreeze and Engine Coolant – A concentrated, phosphate-free option that can be mixed with water for versatile protection.
- AMSOIL Signature Series Fuel-Efficient 100% Synthetic Automatic Transmission Fluid – Withstands heavy towing, high temperatures, and challenging terrain while maintaining fluidity in sub-zero conditions.
- AMSOIL OE Fuel-Efficient 100% Synthetic Automatic Transmission Fluid – Provides reliable protection against wear for standard service intervals.
- AMSOIL SEVERE GEAR® 75W-85 100% Synthetic Gear Lube – Protects differential and transfer case gears against wear and rust while controlling operating temperatures.
- AMSOIL DOT 3 and DOT 4 100% Synthetic Brake Fluid – Ensures excellent ABS responsiveness and stable viscosity across a wide temperature range.
Essential Engine Oil Specifications
Selecting the right viscosity is critical for the 2018 Lexus RX350L’s 3.5L 6-cylinder engine, which uses the 2GR-FKS designation. The manufacturer recommends 0W-20 viscosity for optimal fuel economy and cold-start protection. For this vehicle, the total oil capacity with a filter is 5.8 quarts. If performing a dry fill, the capacity is approximately 5.7 quarts. It is important to refill to the correct level and check the oil after refilling to ensure proper lubrication. The drain plug torque specification should be set to 30 ft/lbs, and a new washer should always be installed on the drain bolt to prevent leaks.
AMSOIL offers four distinct 0W-20 synthetic motor oils tailored to different needs. The Signature Series provides the highest level of protection, with up to 25,000 miles or one year of guaranteed service. It offers 75% more engine protection against horsepower loss and wear compared to industry standards. For drivers looking for a balance of performance and value, the Extended-Life formula offers 20,000 miles of protection with enhanced cleaning power. The OE formula serves as a reliable, cost-effective alternative to conventional oils, while the High-Mileage variant is designed for vehicles with over 75,000 miles to boost detergents and reduce sludge.
Filtration and Cooling Systems
The 2018 RX350L’s cooling system requires a substantial volume of fluid to maintain optimal operating temperatures. The coolant capacity is 13.1 quarts. AMSOIL Passenger Car & Light Truck Antifreeze & Coolant is an ethylene glycol-based 50/50 pre-mix that exceeds original equipment requirements. It is phosphate-, nitrate-, and silicate-free, making it safe for all cooling system metals and compatible with all other antifreeze colors. For those who prefer a concentrated option, the Propylene Glycol Antifreeze can be mixed with distilled water to achieve up to 150,000 miles of protection in passenger cars and light trucks.
Filtration plays a vital role in the longevity of the engine. The AMSOIL Oil Filter (EA15K02) utilizes high-efficiency media that filters out 99% of contaminants at 20 microns. This high capacity for small, wear-causing particles helps reduce engine wear significantly. As an alternative, the WIX Oil Filter (57047) offers premium media that often outperforms OEM-branded filters in terms of dirt holding capacity and flow efficiency. Both filters are designed to be replaced at every oil change to ensure clean oil circulates through the engine. To maintain airflow, the WIX Air Filter ensures optimal filtration for the engine.
Transmission and Drivetrain Care
The 2018 Lexus RX350L is equipped with an automatic transmission that comes in various configurations depending on the drivetrain (AWD or FWD). For the U881E 8-speed AWD transmission, the initial fill capacity is 3.2 quarts, while a total fill requires 7.2 quarts. The U881F 8-speed FWD transmission has similar initial and total fill capacities. Maintaining this fluid is crucial as the transmission endures heavy towing, elevated temperatures, and challenging terrain. AMSOIL Signature Series Fuel-Efficient Automatic Transmission Fluid is engineered to remain fluid in sub-zero temperatures and provides reserve protection during heavy use. The OE Fuel-Efficient variant offers comparable protection for standard maintenance schedules.
The vehicle’s drivetrain also includes a transfer case and a rear differential. For the transfer case, the capacity is approximately 1.7 pints, and for the rear AWD differential, it is about 1.1 pints. Both units utilize a 75W-85 gear oil specification. AMSOIL SEVERE GEAR 75W-85 100% Synthetic Gear Lube is an excellent choice for these components. It contains friction modifiers for limited-slip applications, controls thermal runaway, and helps reduce operating temperatures, extending the life of seals and equipment.
Maintenance Fluids and Protection
Brake fluid maintenance is often overlooked but is essential for safety and performance. The 2018 RX350L uses a DOT 3 hydraulic brake fluid system. AMSOIL DOT 3 and DOT 4 100% Synthetic Brake Fluid offers superior performance with excellent ABS and traction-control responsiveness. It maintains a stable viscosity over a wide temperature range, ensuring consistent brake pedal feel in extreme weather. Additionally, for vehicles that undergo seasonal storage, AMSOIL Gasoline Stabilizer can keep fuel fresh for up to 12 months, while the Engine Fogging Oil protects internal components from rust during periods of inactivity.
About the 2018 Lexus RX350L
The 2018 Lexus RX350L represents the long-wheelbase variant of the fourth-generation RX series, a model that has been a benchmark in the luxury midsize crossover segment for over two decades. Originating from Toyota’s Lexus division, the RX350L was designed specifically to address the growing demand from buyers who required a vehicle that combined the refined ride quality and luxury amenities of a sedan with the practicality of a three-row SUV. The “L” designation indicates an extended wheelbase that provides significantly more rear legroom compared to the standard RX350, making it an ideal choice for families or owners who prioritize passenger comfort.
Under the hood, the 2018 model year continues to utilize the renowned 2GR-FKS 3.5-liter V-6 engine. This powerplant delivers a robust combination of power and efficiency, typically producing around 295 horsepower and 267 lb-ft of torque. The engine features Dual VVT-i (Variable Valve Timing-intelligent) and an Atkinson cycle capability in certain operating conditions to optimize fuel consumption. It is paired with an eight-speed electronically controlled automatic transmission that provides smooth shifts and improved responsiveness. The vehicle is available in both rear-wheel drive and all-wheel-drive configurations, with the AWD systems designed to provide enhanced traction in adverse weather conditions without compromising the vehicle’s agile handling characteristics.
Owners of the 2018 RX350L generally appreciate the vehicle’s quiet cabin, high-quality interior materials, and a suite of advanced safety features known as Lexus Safety System+ A. This technology suite often includes pre-collision systems, adaptive cruise control, and lane departure alert. The vehicle sits on a platform that balances a comfortable, compliant ride with precise steering inputs, making it a favorite for both city commuting and long-distance highway travel. Its market position has been strong, often ranking highly for reliability and resale value, a testament to Lexus’s reputation for building durable and high-value vehicles.
Despite its reliability, the RX350L, like many modern vehicles with direct injection and turbocharged or advanced naturally aspirated engines, can face specific lubrication-related challenges over time. One common issue is the accumulation of carbon deposits on intake valves and fuel injectors, which can occur due to the nature of the Direct Injection system. Using high-quality synthetic motor oils with robust detergent packages, such as AMSOIL Signature Series, can help mitigate this buildup and maintain optimal combustion efficiency. Another potential area of concern is the degradation of seals and gaskets in higher-mileage vehicles, which can lead to oil leaks. The AMSOIL High-Mileage 0W-20 formulation contains special additives that help condition seals and reduce sludge, potentially alleviating leaks and improving engine performance. Additionally, owners have reported issues with excessive engine noise or vibration, often linked to the oil not meeting the high cleanliness standards required for the precise tolerances of the 2GR-FKS engine. Switching to a premium synthetic oil can reduce noise and vibration by ensuring superior lubrication of the variable valve timing components. Finally, while the transmission is generally robust, owners who tow heavy loads or drive in severe conditions may experience transmission fluid breakdown earlier than expected. Regularly changing the transmission fluid to a high-performance synthetic version can prevent wear and extend the service life of the transmission, ensuring smooth operation for the long haul.
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