The 2018 Lexus GS300 is a sophisticated performance sedan that demands precision when it comes to maintenance, particularly for its high-output turbocharged 2.0L engine. Proper lubrication is critical for this specific powerplant, as the 8AR-FTS engine operates under higher temperatures and pressures than standard naturally aspirated engines. Using the correct viscosity and high-quality synthetic additives helps prevent wear on the turbocharger bearings, reduces the risk of oil sludge in the tight oil galleries, and ensures the engine delivers the smooth power delivery the GS300 is known for.
Recommended AMSOIL Products
- AMSOIL Signature Series 0W-20 100% Synthetic Motor Oil – The top choice for unsurpassed engine protection and fuel efficiency, designed to withstand the demands of the turbocharger.
- AMSOIL Extended-Life 0W-20 100% Synthetic Motor Oil – A robust option offering extended drain intervals up to 20,000 miles while maintaining high levels of engine cleanliness.
- AMSOIL OE 0W-20 100% Synthetic Motor Oil – An economical synthetic formula that outperforms conventional oils and meets OEM requirements for this vehicle.
- AMSOIL 0W-20 100% Synthetic High-Mileage Motor Oil – Specifically formulated for vehicles with over 75,000 miles to reduce leaks and consumption while boosting cleaning power.
- AMSOIL Oil Filter – Provides superior filtration efficiency of 99% at 20 microns, protecting the engine from wear-causing contaminants.
- WIX Oil Filter – A premium alternative with media improvements that outperform original equipment manufacturer branded filters.
- AMSOIL Passenger Car & Light Truck Antifreeze & Coolant – A 50/50 pre-mix formulation that protects all cooling system metals, gaskets, and hoses for up to 150,000 miles.
- AMSOIL Propylene Glycol Antifreeze and Engine Coolant – A concentrated, phosphate-free option for maximum corrosion protection in high-mileage or high-performance applications.
- AMSOIL Signature Series Fuel-Efficient 100% Synthetic Automatic Transmission Fluid – Remains fluid in sub-zero temperatures and withstands the rigors of heavy towing and elevated transmission temperatures.
- AMSOIL OE Fuel-Efficient 100% Synthetic Automatic Transmission Fluid – A cost-effective synthetic transmission fluid designed to protect against wear in the AA81E transmission.
- AMSOIL SEVERE GEAR® 75W-90 100% Synthetic Gear Lube – Includes friction modifiers specifically for limited-slip differentials and helps control operating temperatures.
- AMSOIL DOT 3 and DOT 4 100% Synthetic Brake Fluid – Offers excellent ABS responsiveness and a stable viscosity range to ensure safe stopping power.
For the 2018 Lexus GS300 with the 2.0L turbocharged engine, the oil capacity is 4.9 quarts when performing a standard change with a filter replacement. This engine requires an API certified 0W-20 viscosity oil, which provides the optimal balance of cold-weather starting fluidity and high-temperature stability. The 8AR-FTS engine code indicates a direct-injection turbocharged powerplant that benefits significantly from the high-shear stability found in AMSOIL Signature Series, Extended-Life, OE, or High-Mileage motor oils. These formulations contain specialized additives designed to protect turbocharger bearings from coking and wear, which is a common concern for vehicles in this class. By choosing a synthetic oil with high film strength, owners can ensure that critical engine components remain lubricated even during aggressive driving or extended highway commutes.
Beyond the engine, the cooling system requires attention to maintain performance. The 2018 GS300 utilizes a specific AMSOIL Passenger Car & Light Truck Antifreeze & Coolant capacity, with the intercooler holding 2.7 quarts and the engine itself requiring 9.5 quarts of fluid. Using a high-quality antifreeze and AMSOIL Propylene Glycol Antifreeze and Engine Coolant mixture is essential to prevent corrosion within the aluminum components of the cooling system and the turbocharger intercooler. AMSOIL antifreeze options are engineered to exceed original equipment manufacturer requirements, offering protection against rust, scale, and sludge buildup. This ensures that the cooling system remains efficient, preventing overheating issues that can arise from degraded fluids over time.
The transmission fluid is another critical area for this vehicle. The 2018 GS300 is equipped with an 8-speed automatic transmission (AA81E) that requires a full fill of 9.2 quarts for maximum capacity, though an initial fill uses only 3.4 quarts during manufacturing or partial service. Using a synthetic transmission fluid like AMSOIL Signature Series Fuel-Efficient 100% Synthetic Automatic Transmission Fluid can help the transmission shift smoothly and reduce internal friction. This fluid is designed to withstand elevated temperatures and heavy loads, providing a reserve of protection during challenging driving conditions. The OE Fuel-Efficient variant is also available for those seeking a reliable synthetic option that meets original specifications while offering the longevity benefits of synthetic technology.
Maintenance of the differential and braking systems should not be overlooked. The rear limited-slip differential on the GS300 requires a GLS D7 lubricant, and the capacity for the rear differential is 3 pints. AMSOIL SEVERE GEAR 75W-90 100% Synthetic Gear Lube is recommended for this application because it contains specific friction modifiers necessary for limited-slip differentials to function correctly without chattering or slipping. Additionally, the AMSOIL DOT 3 and DOT 4 100% Synthetic Brake Fluid is the recommended hydraulic fluid for this vehicle. It provides a high boiling point and consistent viscosity, ensuring responsive braking performance in all weather conditions.
About the Vehicle
The 2018 Lexus GS300 represents a significant moment in the history of the GS lineage, marking the introduction of the GS 300 model with the 2.0-liter turbocharged engine. While the GS series has long been celebrated for its rear-wheel-drive dynamics and balance between luxury and performance, the 2018 model year brought a new level of efficiency without sacrificing the engaging driving character that Lexus enthusiasts appreciate. This generation of the GS is built on Toyota’s New Global Architecture (TNGA) platform, which contributes to a lower center of gravity and improved rigidity compared to previous generations. The 2.0L 4-cylinder engine, known by the internal code 8AR-FTS, is a turbocharged unit that delivers power through a direct-injection system, offering a blend of responsiveness and fuel economy that appealed to a modern buyer seeking a premium sedan.
Owners of the 2018 Lexus GS300 often praise the vehicle for its refined interior, quiet cabin, and precise steering. The car serves as a sporty luxury sedan that competes in a segment dominated by European rivals, yet it stands out for its reputation for reliability and lower long-term ownership costs. The turbocharged nature of the engine adds a layer of complexity to the powertrain, making the quality of the lubricants used in the engine and transmission even more vital. The turbocharger spins at incredibly high speeds and operates at high temperatures, requiring oil that can maintain its protective film and resist breakdown under thermal stress. Proper fluid maintenance is therefore not just about following a schedule but about preserving the mechanical integrity of this high-performance powertrain.
Like many modern vehicles with turbocharged direct-injection engines, the 2018 GS300 can be susceptible to certain mechanical challenges that can be mitigated through high-quality lubrication. One common issue in this engine family can be the formation of carbon deposits on the intake valves due to direct injection, which can impact airflow and efficiency over time. While AMSOIL P.i.® Performance Improver Gasoline Additive can help clean these injectors and intake components, using a high-quality synthetic motor oil from the start helps keep the internal engine components clean and reduces the rate of deposit formation. Another potential concern is turbocharger wear, particularly if the vehicle is driven aggressively or used for towing. The oil must remain stable to lubricate the turbo bearings, and the use of an extended-life or high-detergent synthetic oil helps prevent the coking and sludge that can lead to premature bearing failure.
Additionally, owners may experience brake fade or reduced responsiveness if the brake fluid absorbs moisture over time, a common issue in all vehicles but critical in a performance sedan like the GS. Regular fluid changes with a high-performance synthetic brake fluid can maintain the hydraulic pressure and boiling points required for consistent braking. Furthermore, the cooling system in the GS300, which is critical for managing the heat of the turbocharger and intercooler, can suffer from corrosion if the coolant degrades. A high-quality antifreeze protects the aluminum components of the engine and cooling system from rust and erosion. Finally, the limited-slip differential in the rear axle requires specific friction modifiers to operate correctly; without the right gear lube, the differential may chatter or slip, affecting traction and handling. Addressing these areas with the correct AMSOIL products ensures the 2018 Lexus GS300 continues to perform as the reliable, high-performance luxury sedan it is designed to be.