The 2018 Lexus IS350 features a sophisticated 3.5-liter V6 engine known for its smooth power delivery and refined driving dynamics. To maintain this high level of performance and reliability, selecting the correct synthetic lubricants is essential. Unlike conventional oils, AMSOIL synthetic motor oils are engineered to withstand the extreme temperatures and high-rpm conditions common in luxury sport sedans. Proper fluid selection ensures optimal viscosity control, superior wear protection, and extended service intervals, allowing the engine to operate at its peak efficiency for years to come.
Recommended AMSOIL Products
- AMSOIL Signature Series 0W-20 100% Synthetic Motor Oil – Offers unsurpassed engine protection with up to 25,000 miles of coverage and 75% more protection against horsepower loss.
- AMSOIL Extended-Life 0W-20 100% Synthetic Motor Oil – Provides 20,000 miles of protection with enhanced cleaning power to keep the engine running smoother and longer.
- AMSOIL OE 0W-20 100% Synthetic Motor Oil – A cost-effective option that fights sludge and deposits with a 100% synthetic formulation designed for OE mileage intervals.
- AMSOIL 0W-20 100% Synthetic High-Mileage Motor Oil – Specifically formulated for engines with over 75,000 miles, featuring boosted detergents to reduce sludge by 67%.
- AMSOIL Oil Filter – Delivers 99 percent filtering efficiency at 20 microns, providing greater capacity for contaminants and lower restriction than standard filters.
- WIX Oil Filter – Offers premium media that improves upon original equipment manufacturer filters, compatible with OE recommended intervals.
- AMSOIL Passenger Car & Light Truck Antifreeze & Coolant – A unique poly-organic acid formulation providing up to 150,000 miles of protection for the cooling system.
- AMSOIL Propylene Glycol Antifreeze and Engine Coolant – A concentrated option that greatly surpasses standards for metallic corrosion and erosion protection.
- AMSOIL Signature Series Fuel-Efficient 100% Synthetic Automatic Transmission Fluid – Designed to withstand heavy towing and elevated temperatures while remaining fluid in sub-zero conditions.
- AMSOIL OE Fuel-Efficient 100% Synthetic Automatic Transmission Fluid – Protects against wear and provides fuel efficiency for vehicles requiring OE specifications.
- AMSOIL SEVERE GEAR® 80W-90 100% Synthetic Gear Lube – Advanced protection against wear and thermal runaway for differential and transfer case applications.
- AMSOIL SEVERE GEAR® 75W-90 100% Synthetic Gear Lube – Contains friction modifiers for limited-slip applications and helps reduce operating temperatures.
- AMSOIL SEVERE GEAR® 75W-110 100% Synthetic Gear Lube – Provides robust protection against wear in heavy-duty gear applications.
- AMSOIL SEVERE GEAR® 75W-85 100% Synthetic Gear Lube – Ideal for front differential applications requiring GL-5 specification in colder temperatures.
- AMSOIL DOT 3 and DOT 4 100% Synthetic Brake Fluid – Ensures excellent ABS and traction-control responsiveness with stable viscosity over a wide temperature range.
- AMSOIL P.i. Performance Improver Gasoline Additive – Restores up to 14% horsepower and cleans GDI fuel injectors after one tank of fuel.
Understanding the specific fluid requirements for the 2018 IS350 is crucial for preserving the vehicle’s longevity. The engine demands 0W-20 viscosity motor oil to ensure proper lubrication during cold starts while maintaining a protective film at operating temperatures. The total fluid capacity for a change with a filter is 6.8 quarts. Whether you are driving in severe climates or pushing the vehicle on winding roads, the thermal stability of synthetic fluids prevents breakdown and protects critical internal components from wear. The cooling system requires a specific antifreeze formulation to manage the high heat generated by the 2GR-FKS engine, with a total capacity of 9.9 quarts for the system. Using the AMSOIL Passenger Car & Light Truck Antifreeze & Coolant ensures the cooling system metals, gaskets, and hoses are protected against corrosion and freezing.
Transmission and Drivetrain Fluids
The automatic transmission in this model varies slightly by drive configuration, but both types benefit greatly from synthetic fluid. For the 6-speed AWD transmission (A760H), the total fill capacity is 10.6 quarts, while the 8-speed RWD unit (AA81E) requires 10 quarts. Initial fills for these transmissions are significantly lower, at 1.7 and 3.4 quarts respectively. Using a synthetic transmission fluid like the Signature Series Fuel-Efficient 100% Synthetic Automatic Transmission Fluid ensures the transmission shifts smoothly and resists the harsh conditions of stop-and-go traffic or spirited driving. The fluid remains fluid even in sub-zero temperatures, providing reserve protection during heavy use. For vehicles prioritizing fuel economy and OE specifications, the AMSOIL OE Fuel-Efficient 100% Synthetic Automatic Transmission Fluid is an excellent choice to protect against wear while maintaining efficiency.
Gear Lubrication and Braking Systems
For the differential and transfer case, the requirements depend on the specific axle configuration and ambient temperatures. Front differentials on AWD models typically require 1.5 pints of fluid. Depending on the temperature range, either 80W-90 or 75W-85 synthetic gear lube is appropriate. For the rear differential, the capacity is 3 pints, with specifications for standard, limited-slip, and GL-5 applications. AMSOIL SEVERE GEAR® 75W-85 and 75W-90 products provide the necessary extreme pressure additives and friction modifiers to protect these components, especially in limited-slip differentials where friction modifiers are essential. Finally, the braking system utilizes DOT 3 hydraulic fluid. AMSOIL’s synthetic DOT 3 and DOT 4 100% Synthetic Brake Fluid offers superior resistance to boiling points and moisture absorption, ensuring consistent pedal feel and safety.
About the Vehicle
The 2018 Lexus IS350 is the third generation of the brand’s compact executive sedan, representing a significant evolution in the vehicle’s handling and refinement. Based on the Toyota K platform, this model combines a naturally aspirated 3.5-liter V6 engine with either a rear-wheel-drive or all-wheel-drive configuration. This powertrain, designated as the 2GR-FKS, is renowned for its reliability and smooth power delivery, producing approximately 300 to 320 horsepower depending on the source and specific market tuning. The IS350 occupies a unique space in the market, offering the luxurious appointments and build quality associated with the Lexus brand while maintaining a sporty driving character that competes with German rivals like the BMW 3 Series and Mercedes-Benz C-Class.
Owners of the IS350 appreciate its balanced chassis and precise steering, which make it engaging on twisty roads. The interior is typically praised for its quietness, high-quality materials, and advanced technology features available for the 2018 model year. However, like any high-performance vehicle, the IS350 can face specific issues over time that can be mitigated with the right maintenance products. One common concern among high-mileage owners is engine sludge buildup, particularly if the vehicle has been subjected to frequent short trips where the oil does not fully warm up. Using a high-performance synthetic oil like AMSOIL 0W-20 100% Synthetic High-Mileage Motor Oil helps combat this by cleaning the engine and preventing deposit formation. Another effective method to maintain engine cleanliness is using AMSOIL P.i. Performance Improver, which restores injectors and horsepower.
Another area of focus for owners is the transmission’s shift quality. Some drivers report hesitation or rough shifts, which can sometimes be attributed to fluid degradation over time. Flushing the transmission with a high-quality synthetic fluid can restore smooth shifting performance. Additionally, the IS350’s direct injection GDI engine can accumulate carbon deposits on intake valves and fuel injectors, potentially leading to reduced fuel economy and power. The use of a performance fuel additive like AMSOIL P.i. can help restore lost horsepower and improve injector flow. Finally, brake fluid hygroscopy is a common issue in many vehicles, where moisture absorption lowers the boiling point of the fluid. Switching to a synthetic brake fluid prevents this boiling and ensures the braking system remains responsive under heavy use, a critical factor for a vehicle with the IS350’s dynamic capabilities. For vehicle care and exterior protection, owners may also consider AMSOIL High-Foam Car Shampoo or AMSOIL Exterior Ceramic Spray to maintain the IS350’s pristine appearance.
By adhering to a strict maintenance schedule using these specialized fluids, owners can ensure their 2018 Lexus IS350 continues to perform with the precision and luxury it was designed to deliver. Whether for daily commuting or spirited weekend drives, the right lubricants provide the foundation for a trouble-free ownership experience.