The 2018 Lexus IS300 represents a significant engineering milestone for the brand, particularly with the introduction of the compact 2.0-liter turbocharged engine. This powertrain, known as the 8AR-FTS, combines efficiency with spirited performance, delivering a driving experience that balances daily usability with the dynamic character Lexus enthusiasts expect. However, high-efficiency turbocharged engines place unique demands on lubrication systems. The high operating temperatures generated by the turbocharger and the precise tolerances of the modern engine require oils that offer superior thermal stability and film strength to prevent wear and sludge formation. Using the correct fluids is not just about maintaining a warranty; it is about ensuring the longevity of the engine’s internal components, protecting the turbocharger from oil coking, and maintaining optimal fuel economy.
Recommended AMSOIL Products
AMSOIL provides a comprehensive range of synthetic lubricants specifically engineered to meet or exceed the severe service demands of the 2018 Lexus IS300. These products are designed to withstand the high temperatures of the turbocharged engine while providing the necessary protection for extended intervals.
- AMSOIL Signature Series 0W-20 100% Synthetic Motor Oil – The top choice for this vehicle, offering unsurpassed engine protection against horsepower loss and wear, with a guaranteed service life of up to 25,000 miles or one year. It features 75% more engine protection compared to industry standards.
- AMSOIL Extended-Life 0W-20 100% Synthetic Motor Oil – An excellent alternative for those seeking a balance between performance and extended change intervals, providing up to 20,000 miles of guaranteed protection and superior cleaning power to keep the engine running smoother.
- AMSOIL OE 0W-20 100% Synthetic Motor Oil – Designed to fit OEM specifications while outperforming conventional oils, this fluid helps fight sludge and deposits with a robust 100% synthetic formulation and protects turbochargers effectively.
- AMSOIL 0W-20 100% Synthetic High-Mileage Motor Oil – Ideally suited for vehicles with over 75,000 miles, this oil contains a boosted detergent package to reduce sludge and enhance cleaning power, ensuring the engine performs better for longer.
- AMSOIL Oil Filter – This premium filter offers 99 percent efficiency at 20 microns, allowing for lower restriction to keep engine parts lubricated and providing greater capacity for small, wear-causing contaminants to reduce engine wear.
- WIX Oil Filter – A premium media filter that offers improvements over original equipment manufacturer-branded filters, making it a solid choice for drivers looking for high-quality filtration at an accessible price point.
- AMSOIL Passenger Car & Light Truck Antifreeze & Coolant – A unique poly-organic acid (OAT) formulation that protects all cooling system metals, gaskets, and hoses for up to 150,000 miles or five years, ensuring the engine stays at optimal temperature.
- AMSOIL Signature Series Fuel-Efficient 100% Synthetic Automatic Transmission Fluid – This fluid withstands the rigors of heavy towing, elevated temperatures, and challenging terrain, providing reserve protection during heavy use while maintaining fluidity in sub-zero conditions.
- AMSOIL SEVERE GEAR® 75W-85 100% Synthetic Gear Lube – Recommended for the rear differential, this lube provides advanced protection against wear and rust while controlling thermal runaway, which is crucial for the longevity of the gear set.
- AMSOIL DOT 3 and DOT 4 100% Synthetic Brake Fluid – This synthetic brake fluid ensures excellent ABS and traction-control responsiveness with a stable viscosity over a wide temperature range, offering superior safety and performance compared to conventional fluids.
Engine Oil Specifications and Service Capacities
The heart of the 2018 Lexus IS300 is the 2.0-liter 4-cylinder engine, identified by the engine code 8AR-FTS. This turbocharged powerplant requires a viscosity grade of 0W-20 to ensure proper flow during cold starts and sufficient film strength at high operating temperatures. The total capacity for the engine, including the filter replacement, is 4.9 quarts. After refilling, it is critical to check the oil level to ensure it is within the proper operating range. The oil drain plug should be torqued to 30 ft-lbs, and a new washer should always be installed on the drain bolt to prevent leaks.
For engine oil, AMSOIL Signature Series 0W-20 100% Synthetic Motor Oil stands out as the premier choice. It is formulated to provide 75% more engine protection against horsepower loss and wear compared to industry standards. This oil is ideal for drivers who push their vehicles hard or engage in severe driving conditions, as it offers guaranteed protection for up to 25,000 miles or one year. The high-quality base stocks and additive packages help protect turbochargers from coking, a common issue in turbocharged engines where oil breaks down due to excessive heat after the engine is turned off.
For those seeking a slightly longer interval but still excellent protection, the AMSOIL Extended-Life 0W-20 100% Synthetic Motor Oil is a robust option. It provides up to 20,000 miles of protection and offers 37% more cleaning power to keep the engine running smoothly over time. It effectively fights Low-Temperature Pre-Ignition (LSPI), a phenomenon that can cause severe engine damage in direct injection turbocharged engines.
If you are looking for a cost-effective solution that still outperforms conventional oils and meets OEM mileage expectations, the AMSOIL OE 0W-20 100% Synthetic Motor Oil is an excellent candidate. It is designed to fight sludge and deposits effectively while providing reliable protection. For vehicles that have accumulated significant mileage, the AMSOIL 0W-20 100% Synthetic High-Mileage Motor Oil is specifically formulated to address the wear and tear of older engines, featuring enhanced anti-wear additives and a reduced sludge formulation.
Filtration and Cooling System Care
Using high-quality motor oil is only half the equation; effective filtration is essential to remove contaminants. The AMSOIL Oil Filter is engineered to filter at 99 percent efficiency at 20 microns, which helps reduce engine wear significantly. It features greater capacity for contaminants compared to many competing filters and offers an extended service life to match the extended mileage of AMSOIL synthetic oils. For owners who prefer a trusted aftermarket brand, the WIX Oil Filter is a compatible option that offers premium media improvements over OEM filters.
The cooling system of the 2018 IS300 requires careful maintenance due to the high thermal loads from the turbocharger. The engine coolant capacity is 8.2 quarts, with an additional 3.2 quarts required for the intercooler. The AMSOIL Passenger Car & Light Truck Antifreeze & Coolant is a 50/50 pre-mix formulation that protects all cooling system metals, gaskets, and hoses. It is free of phosphates, nitrates, nitrites, silicates, borates, and amines, ensuring compatibility with all other antifreeze colors and providing protection for up to 150,000 miles or five years. For those who prefer a concentrated solution, the AMSOIL Propylene Glycol Antifreeze and Engine Coolant offers a durable alternative that requires mixing with distilled water.
Transmission, Differential, and Brake Fluid
The 2018 Lexus IS300 is equipped with an AA81E automatic transmission. The capacity for the automatic transmission is 3.4 quarts for an initial fill, with a total fill capacity of 9.2 quarts for an 8-speed variant. Using a fluid that can handle high temperatures and heavy loads is vital for shifting performance and longevity. The AMSOIL Signature Series Fuel-Efficient 100% Synthetic Automatic Transmission Fluid is designed to withstand the rigors of heavy towing and elevated temperatures while remaining fluid in sub-zero conditions. Alternatively, the AMSOIL OE Fuel-Efficient 100% Synthetic Automatic Transmission Fluid offers reliable protection against wear for standard driving conditions.
For the rear differential, the recommended lubricant is a GL-5 compatible 75W-85 fluid. The capacity for the rear differential is 3 pints. The AMSOIL SEVERE GEAR® 75W-85 100% Synthetic Gear Lube is the ideal choice, offering advanced protection against wear and helping to reduce operating temperatures. It contains friction modifiers suitable for limited-slip applications and controls thermal runaway effectively.
Brake fluid is another critical component often overlooked. The 2018 IS300 requires a DOT 3 hydraulic brake fluid. The AMSOIL DOT 3 and DOT 4 100% Synthetic Brake Fluid provides excellent responsiveness for ABS and traction control systems. Its stable viscosity over a wide temperature range ensures consistent braking performance in both hot and cold conditions, enhancing vehicle safety.
About the Vehicle
The 2018 Lexus IS300 occupies a unique space in the compact luxury sedan market. It marks the first time Lexus offered a turbocharged engine option in the IS lineup, shifting the focus towards a more engaging, “sporty” driving character while maintaining the brand’s hallmark reliability and refinement. The vehicle is built on the Toyota New Global Architecture (TNGA) platform, which lowers the center of gravity and improves chassis rigidity, resulting in sharper handling and a more connected feel to the road compared to previous generations.
Equipped with the 2.0-liter 4-cylinder turbocharged engine (8AR-FTS), the IS300 delivers around 240 horsepower, providing sufficient power for spirited driving and confident merging. The turbocharging system allows for high torque availability at low RPMs, making the car feel punchy in everyday traffic. The interior design emphasizes driver-centric ergonomics, with a focus on quality materials and a sophisticated cockpit layout that includes available features like a 10.3-inch navigation display and premium audio systems. The rear-seat space, while adequate for a compact sedan, is best suited for occasional use, keeping the focus on front-seat occupants.
Despite its reliability pedigree, the 2018 IS300 can encounter specific issues that proper lubrication can help mitigate. One common concern with turbocharged engines is turbocharger oil coking. When the engine is shut off immediately after hard driving, heat soak can cause the oil in the turbo bearings to bake and form carbon deposits, leading to bearing failure. Using a high-quality synthetic oil with excellent thermal stability helps prevent this buildup. Another potential issue is sludge formation, particularly in the oil gallery and valve cover, which can restrict oil flow and cause premature wear. AMSOIL’s high-detergent synthetic oils are formulated to keep internal engine components clean, preventing these deposits from forming.
Additionally, owners of turbocharged vehicles may experience higher engine oil consumption over time due to the increased stress on piston rings and valve stem seals. While not a defect, this is a natural wear characteristic in high-temperature engines. The AMSOIL 0W-20 100% Synthetic High-Mileage Motor Oil includes additives designed to condition seals and reduce oil consumption, helping to maintain optimal oil levels for longer periods. Finally, the high-performance nature of the vehicle means that the transmission fluid is subjected to significant thermal stress. Over time, transmission fluid can break down, leading to harsh shifts. Regular fluid changes with a synthetic fluid designed for high temperatures help maintain smooth shifting and extend the life of the transmission components.
By selecting the appropriate AMSOIL synthetic lubricants, owners can ensure their 2018 Lexus IS300 receives the highest level of protection available. Whether you are a daily commuter or a driving enthusiast who appreciates the dynamic capabilities of the IS300, using the right fluids is the best way to preserve the vehicle’s performance and value for years to come. From the engine’s turbocharger to the rear differential, each component benefits from the advanced chemistry found in AMSOIL products, providing a comprehensive solution for all lubrication needs.