The 2018 Toyota Highlander equipped with the 2.7-liter four-cylinder engine is a staple of family transportation, known for its blend of reliability and efficiency. However, to ensure this vehicle delivers its full potential over many years, the engine and its internal components require lubrication systems that outperform standard factory fluids. Using the correct viscosity and high-quality synthetic formulations is essential for maintaining fuel economy, preventing wear, and extending the service life of the powertrain. This guide provides a comprehensive breakdown of the recommended lubricants, capacities, and specific AMSOIL products designed to meet the rigorous demands of the 2018 Toyota Highlander’s 1AR-FE engine.
Recommended AMSOIL Products
- AMSOIL Signature Series 0W-20 100% Synthetic Motor Oil – Provides unsurpassed engine protection for up to 25,000 miles or one year, offering 75% more resistance to horsepower loss and wear compared to industry standards.
- AMSOIL Extended-Life 0W-20 100% Synthetic Motor Oil – Delivers up to 20,000 miles of protection between changes with 37% more cleaning power to help keep the engine running smoother for longer.
- AMSOIL OE 0W-20 100% Synthetic Motor Oil – An excellent choice for those seeking factory performance with a 100% synthetic formulation that fights sludge and deposits while meeting OEM requirements.
- AMSOIL 0W-20 100% Synthetic High-Mileage Motor Oil – Specifically formulated for vehicles with over 75,000 miles, featuring boosted detergents and reduced sludge to improve engine performance.
- AMSOIL Oil Filter – Ensures 99% filtration efficiency at 20 microns, offering greater capacity for contaminants and lower restriction to keep engine parts properly lubricated.
- WIX Oil Filter – A premium alternative with media that offers improvements over original equipment manufacturer branded filters.
- WIX Air Filter – Premium media offers improvements over original equipment manufacturer (OEM)-branded filters for better airflow.
- AMSOIL Signature Series Fuel-Efficient 100% Synthetic Automatic Transmission Fluid – Withstands heavy towing and elevated temperatures, remaining fluid in sub-zero conditions for optimal transmission performance.
- AMSOIL OE Fuel-Efficient 100% Synthetic Automatic Transmission Fluid – Protects against wear while maintaining fuel efficiency, making it a top choice for standard operating conditions.
- AMSOIL SEVERE GEAR® 75W-85 100% Synthetic Gear Lube – Provides advanced protection for differential and transfer cases, controlling thermal runaway and reducing operating temperatures.
- AMSOIL Passenger Car & Light Truck Antifreeze & Coolant – A unique OAT formulation providing protection for up to 150,000 miles or five years, safe for all cooling system metals and compatible with all coolant colors.
- AMSOIL Propylene Glycol Antifreeze and Engine Coolant – A concentrated, non-toxic coolant option that offers protection up to 150,000 miles or five years for passenger cars and light trucks.
- AMSOIL DOT 3 and DOT 4 100% Synthetic Brake Fluid – Delivers excellent ABS and traction-control responsiveness with stable viscosity over a wide temperature range.
Selecting the right motor oil begins with understanding the specific requirements of the 2018 Highlander’s 2.7-liter engine code 1AR-FE G. This engine is designed to operate best with 0W-20 viscosity oil, which offers the ideal balance of fuel economy and cold-weather starting performance. When changing the oil, the total capacity required is 4.6 quarts, including the filter. It is crucial to ensure the oil level is checked after the refill and that the drain plug is torqued to 30 ft/lbs, using a new washer on the drain bolt to prevent leaks.
The Signature Series 0W-20 stands out as the ultimate choice for maximum protection, allowing for service intervals of up to 25,000 miles or one year. For drivers who prefer a slightly more conservative approach or need an oil that outperforms conventional oils without the premium price point of the AMSOIL OE Motor Oil, the OE 0W-20 is a fantastic alternative. This oil is designed to fight sludge and deposits while maintaining the synthetic benefits required by modern engines. Additionally, for High-Mileage owners with over 75,000 miles on their Highlander, the AMSOIL 0W-20 High-Mileage formulation includes enhanced anti-wear additives and a boosted detergent package to reduce sludge by 67% and help the engine last longer.
Filtration is just as critical as the oil itself. The AMSOIL Oil Filter (EA15K02-EA) is engineered to provide superior filtering efficiency and capacity compared to many competing filters. It helps reduce engine wear by capturing small, wear-causing contaminants and allows for lower restriction, ensuring engine parts stay lubricated even during high-demand driving. For those who prefer a well-known aftermarket brand, the WIX Oil Filter is also a viable option, offering premium media that improves upon OEM-branded filters. If the Highlander is equipped with a 4WD system, the differential and transfer case lubrication also requires attention. The transfer case requires 1.7 pints of lubricant, while the rear AWD differential needs 1.1 pints. AMSOIL SEVERE GEAR® 75W-85 Synthetic Gear Lube is recommended for these components, as it contains friction modifiers for limited-slip applications and helps reduce operating temperatures significantly.
Fluid System and Cooling Requirements
Proper fluid maintenance extends beyond the engine. The cooling system for the 2018 Highlander with this engine has a total capacity of 10.7 quarts. Ensuring the antifreeze and coolant is up to spec is vital for preventing overheating and corrosion within the aluminum engine block and radiator. The AMSOIL Passenger Car & Light Truck Antifreeze & Coolant is a phosphate-, nitrate-, nitrite-, silicate-, borate-, and amine-free formulation that protects all cooling system metals, gaskets, and hoses. It is available as a 50/50 pre-mix ethylene glycol solution, ready for immediate use, or as a concentrated propylene glycol option for those who prefer mixing their own solutions. The AMSOIL Propylene Glycol Antifreeze and Engine Coolant is particularly noted for its non-toxic properties and ability to protect against metallic corrosion and erosion, offering up to 150,000 miles or five years of service life.
The automatic transmission in the 2018 Highlander is a 6-speed unit (U760E). While the initial fill capacity is 2.9 quarts, a total fill for maintenance purposes requires 6.9 quarts of fluid. The transmission is subjected to significant heat and stress, especially during towing or driving in challenging terrain. AMSOIL Signature Series Fuel-Efficient Automatic Transmission Fluid is designed to withstand these rigors, remaining fluid in sub-zero temperatures and providing reserve protection during heavy use. The AMSOIL OE Fuel-Efficient Automatic Transmission Fluid is another excellent option that protects against wear while maintaining the fuel efficiency that Toyota drivers expect. For the braking system, which relies on a hydraulic DOT 3 fluid, AMSOIL DOT 3 and DOT 4 100% Synthetic Brake Fluid ensures a stable viscosity across a wide temperature range. This synthetic formulation improves ABS and traction-control responsiveness, a noticeable upgrade over conventional organic fluids that can boil under heavy braking.
Seasonal storage and long-term maintenance also play a role in vehicle longevity. For owners who store their Highlander for extended periods, AMSOIL Gasoline Stabilizer can keep fuel fresh for up to 12 months, protecting against varnish, gum, and ethanol corrosion. Similarly, AMSOIL Engine Fogging Oil is highly effective for preventing rust on internal engine components during inactivity. To further enhance performance and fuel economy, AMSOIL P.i.® Performance Improver can be added to the fuel tank to restore up to 14% horsepower and clear carbon deposits from GDI fuel injectors. These additives, along with proper filter changes like the WIX Air Filter for cleaner airflow, ensure the vehicle operates at its peak efficiency.
Vehicle Background
The 2018 Toyota Highlander represents a mature generation of one of the most popular midsize SUVs in North America. As a crossover utility vehicle, the Highlander bridges the gap between a car-like driving experience and the practical utility of a truck-based SUV. The 2018 model year continued the legacy of the fourth generation, which debuted in 2014, known for its bold exterior design, spacious interior, and high safety ratings. When equipped with the 2.7-liter 4-cylinder engine (1AR-FE), the Highlander offers a balance of affordability and sufficient power for daily family duties, delivering a smooth and quiet ride that prioritizes comfort over aggressive sportiness.
Owners of the 2018 Highlander with the 2.7L engine often appreciate the vehicle’s reliability and fuel efficiency. The 4-cylinder powertrain, paired with a six-speed automatic transmission, provides adequate acceleration for highway merging and overtaking, while maintaining better fuel economy figures compared to the V6 options. The vehicle is built on a platform that emphasizes safety, typically boasting top-tier crash test results and a wide array of standard driver-assist features. It is a front-wheel-drive based AWD system that automatically engages the rear wheels when slip is detected, making it a competent choice for light snow and inclement weather, though it is not designed for serious off-road exploitation.
Despite its reputation for durability, there are known issues that owners of the 2018 Highlander should be aware of, and where synthetic lubrication can provide a significant advantage. One common concern for the 1AR-FE engine is oil sludge buildup, particularly if the vehicle has been driven with conventional oils or if short-trip driving is prevalent. This can lead to clogged oil passages and increased wear. Using a high-quality synthetic oil like the AMSOIL Signature Series or AMSOIL Extended-Life formulations helps keep the engine cleaner and prevents the formation of sludge deposits, ensuring better oil flow to critical components.
Another area where the 2018 Highlander can experience wear is in the transmission fluid, especially if the vehicle is used for frequent towing or hauling. The fluid can degrade faster than expected, leading to harsh shifting or premature wear of the clutch packs. Switching to a high-performance synthetic transmission fluid can mitigate these issues by providing superior thermal stability and oxidation resistance, extending the life of the transmission. Additionally, the cooling system can be susceptible to corrosion over time, especially if the coolant is not flushed and replaced according to schedule. AMSOIL’s phosphate-free antifreeze and coolants address this by providing long-term corrosion protection without the abrasive particles found in traditional coolants. Finally, some owners report issues with the brakes developing a squeal or reduced responsiveness over time. The boiling point of standard DOT 3 fluid can drop under repeated hard stops, compromising performance. Upgrading to a synthetic DOT 3/4 brake fluid raises the boiling point significantly, restoring crisp pedal feel and ABS responsiveness, and ensuring safer stopping power in emergency situations.
By staying on top of fluid maintenance with premium synthetic products, Highlander owners can address these potential weaknesses proactively. The 2.7L Highlander remains a beloved family hauler, and ensuring it is protected with the right lubricants will keep it running smoothly for miles to come. Whether it is the motor oil that needs to be changed every 25,000 miles or the coolant that needs to be refreshed, the right choice of fluids makes all the difference in the long-term health of the vehicle.