The 2018 Toyota Highlander equipped with the 3.5L V6 (engine code 2GR-FXS I) is a robust midsized SUV known for its reliability and smooth performance. However, achieving peak durability and fuel economy from this powertrain requires a precise selection of synthetic lubricants. Using the correct viscosity and high-quality additives ensures that the engine, Signature Series Motor Oil, transmission, and braking systems operate with minimal friction and maximum protection, even under the stresses of daily commuting, towing, or extreme weather conditions.
Recommended AMSOIL Products
- AMSOIL Signature Series 0W-20 100% Synthetic Motor Oil – Offers unmatched protection for up to 25,000 miles and superior resistance to horsepower loss and wear, making it the ultimate choice for high-performance longevity.
- AMSOIL 0W-20 100% Synthetic Hybrid Motor Oil – Specially formulated for hybrid engines like this one, providing superior sludge control and enhanced corrosion protection to maximize fuel economy.
- AMSOIL Extended-Life 0W-20 100% Synthetic Motor Oil – Delivers 37% more cleaning power to keep the engine running smoother and longer, with guaranteed protection for 20,000 miles between changes.
- AMSOIL OE 0W-20 100% Synthetic Motor Oil – A cost-effective, full synthetic option that fights sludge and deposits effectively while meeting the manufacturer’s specifications for OEM-equivalent protection.
- AMSOIL 0W-20 100% Synthetic High-Mileage Motor Oil – Designed for vehicles over 75,000 miles, featuring boosted detergents to reduce sludge and protect against leaks and oil consumption.
- AMSOIL Oil Filter EA15K02-EA – Provides 99% filtering efficiency at 20 microns with greater capacity for small, wear-causing contaminants to ensure extended service life and lower restriction.
- WIX Oil Filter 57047-EA – Offers premium filtration media that provides improvements over standard original equipment manufacturer branded filters.
- AMSOIL Signature Series Fuel-Efficient 100% Synthetic Automatic Transmission Fluid – Withstands the rigors of heavy towing and elevated temperatures while maintaining fluidity in sub-zero conditions.
- AMSOIL OE Fuel-Efficient 100% Synthetic Automatic Transmission Fluid – Provides cost-effective protection against transmission wear while meeting the vehicle’s specific requirements.
- AMSOIL Passenger Car & Light Truck Antifreeze & Coolant – A 50/50 pre-mixed ethylene glycol formulation that protects all cooling system metals and hoses for up to 150,000 miles or 5 years.
- AMSOIL Propylene Glycol Antifreeze and Engine Coolant – A concentrated coolant that requires mixing, offering exceptional corrosion protection and a service interval of up to 150,000 miles.
- AMSOIL DOT 3 and DOT 4 100% Synthetic Brake Fluid – Delivers excellent ABS and traction-control responsiveness with a stable viscosity over a wide temperature range to prevent brake fade.
- AMSOIL P.i. Performance Improver Gasoline Additive – Restores up to 14% horsepower and cleans GDI fuel injectors to 100% flow rate, improving fuel economy and reducing the need for higher-octane fuel.
Understanding the 2GR-FXS I Engine Requirements
The 2018 Toyota Highlander 3.5L V6 is powered by the 2GR-FXS I engine, a naturally aspirated, dual VVT-i (Variable Valve Timing intelligence) unit. This engine design places a high premium on viscosity stability and deposit control. While Toyota specifies 0W-20 motor oil for this application, standard conventional oils can break down faster under the thermal stress of the aluminum block and head. AMSOIL Signature Series oils are engineered to maintain their viscosity index far beyond the capabilities of mineral-based oils, ensuring that the critical 0W-20 grade protects the engine during cold starts while providing a robust lubricating film at operating temperatures.
The total oil capacity for the 2018 Highlander with the 3.5L engine is 5.8 quarts when including the AMSOIL Oil Filter change. This specific volume is crucial to ensure the oil pump can maintain proper pressure across the entire lubrication system, from the main bearings to the dual VVT-i actuators. Underfilling can lead to aeration and reduced pump efficiency, while overfilling can cause excessive crankcase pressure and oil leaks. After refilling to the specified capacity, the oil level must be checked on the dipstick to confirm the reading is within the safe operating zone.
When performing this service, the oil drain plug should be torqued to 30 ft/lbs. It is essential to install a new washer on the drain bolt during every oil change to ensure a leak-free seal. The filter replacement interval is another area where synthetic lubricants excel. While conventional filters and oils often require changes every 5,000 to 7,500 miles, Signature Series Oil and the AMSOIL Oil Filter allow for intervals up to 25,000 miles or one year, whichever comes first, under normal driving conditions. This flexibility reduces maintenance costs and waste without sacrificing engine protection.
Transmission and Cooling System Protection
The automatic transmission in the 2018 Highlander is a critical component that requires precise fluid properties. The total fill capacity for the automatic transmission is 4.9 quarts. Using the correct fluid is vital for the longevity of the transmission clutches, bands, and torque converter. AMSOIL Signature Series Fuel-Efficient Automatic Transmission Fluid is designed to withstand the heat generated during heavy towing or spirited driving. It remains fluid in sub-zero temperatures, ensuring smooth shifting and protection against wear during the coldest starts.
For the cooling system, the Highlander requires a total of 13.1 quarts of AMSOIL Propylene Glycol Antifreeze for the engine, with an additional 2 quarts specifically for the inverter system. Over time, coolant additives deplete, leading to corrosion in the aluminum radiator and engine blocks. AMSOIL Passenger Car & Light Truck Antifreeze & Coolant uses a unique poly-organic acid (OAT) formulation that outperforms traditional green or orange coolants. It is phosphate, nitrate, nitrite, silicate, borate, and amine-free, ensuring compatibility with all cooling system metals, gaskets, and hoses. The engine coolant system should be drained, flushed, and refilled with this formulation to protect against rust, freeze, and boil-over for up to 150,000 miles or 5 years.
AMSOIL DOT 3 and DOT 4 100% Synthetic Brake Fluid is often overlooked but plays a critical role in safety. The 2018 Highlander’s braking system operates under high hydraulic pressure. This synthetic fluid offers a high boiling point that prevents fluid from vaporizing under heavy braking. It maintains a stable viscosity across a wide temperature range, ensuring crisp pedal feel and optimal ABS responsiveness, which is essential for maintaining control in emergency stops.
Additional Maintenance Recommendations
To further enhance the performance and longevity of your vehicle, consider adding AMSOIL P.i. Performance Improver Gasoline Additive. This additive helps clean fuel injectors and combustion chambers, which can restore up to 14% of lost horsepower and significantly improve fuel economy. It is particularly beneficial for vehicles that see short-trip driving where fuel dilution can occur, as it helps prevent carbon buildup and pre-ignition knock.
Special Considerations for High-Mileage Vehicles
If your 2018 Highlander has accumulated over 75,000 miles, the internal engine components may experience slight wear that can lead to oil consumption or minor leaks. In these cases, switching to AMSOIL 0W-20 100% Synthetic High-Mileage Motor Oil is recommended. This formula contains a unique chemistry with boosted detergents and dispersants to clean existing deposits while reducing sludge by 67%. It also features enhanced anti-wear additives and seal conditioners that help reduce oil consumption and prevent leaks, ensuring the engine continues to run smoothly for years to come.
Vehicle Background
The 2018 Toyota Highlander represents a significant chapter in the history of the midsized SUV segment, continuing a legacy of reliability and family-oriented utility that Toyota has cultivated for decades. This particular model year was part of the third generation of the Highlander, which debuted in 2014 and underwent a notable refresh for the 2017 model year. The 2018 iteration retained the popular trim levels that made the vehicle a best-seller, ranging from the practical Base model to the feature-rich Limited and the ruggedly styled XLE V6.
At the heart of the 2018 Highlander is the choice of powertrains, with the 3.5L V6 engine being a favorite among those who prioritize power and towing capability. The 2GR-FXS I engine in question delivers around 295 horsepower and 263 lb-ft of torque, paired with a six-speed automatic transmission. This powertrain setup provides the Highlander with enough oomph to handle highway merging with ease and carry a substantial load, including a tow rating of up to 5,000 pounds when properly equipped. The engine is mated to a transverse front-wheel-drive layout or an available all-wheel-drive system that uses a rear wheel disconnect for improved fuel efficiency when 4WD is not needed.
Toyota’s reputation for longevity is well-earned, and the Highlander has been a cornerstone of that reputation. It was originally developed as a response to the growing demand for a versatile SUV that could accommodate up to eight passengers, offering a spacious interior with a versatile third-row seating arrangement. The 2018 model continued to emphasize safety and technology, typically coming equipped with Toyota Safety Sense P (TSS-P), a suite of active safety features including pre-collision systems, lane departure alert, and automatic high beams. The vehicle’s platform was designed to offer a comfortable, car-like ride quality, making it a preferred choice for suburban families and long-distance road trips alike.
Owners of the 2018 Highlander generally praise the vehicle for its predictable handling and quiet cabin, which are hallmarks of Toyota engineering. The interior space is well-designed, with ample headroom and legroom for both front and rear passengers. However, like any complex machine, this vehicle is not without its quirks. One common issue reported by Highlander owners involves the variable valve timing (VVT) actuators. These components, which control the timing of the engine’s intake and exhaust valves, can occasionally suffer from oil sludge buildup if the oil is not changed frequently or if the oil quality is poor. Sludge in the VVT solenoids can cause the “check engine light” to illuminate with codes related to the valve timing system, and in some cases, lead to rough idling or decreased fuel efficiency.
Another potential concern for the 3.5L engine in these models is carbon buildup on the intake valves. While the direct injection system contributes to lower emissions, it can also lead to carbon deposits on the back of the intake valves, which can eventually affect airflow and engine performance. High-quality synthetic oils with superior detergent packages, such as AMSOIL Signature Series or Extended-Life Motor Oil, can help mitigate this issue by keeping the combustion chamber and valvetrain cleaner for longer intervals.
High-mileage versions of the Highlander can experience oil consumption or minor oil leaks around the valve cover gaskets as the rubber seals age and harden. This is where the specific chemistry of High-Mileage Motor Oil becomes valuable. The additives in these formulations are designed to swell and condition rubber seals, potentially reducing leaks and slowing the rate of oil consumption. Additionally, the Signature Series Automatic Transmission Fluid in some units can become “fried” or degraded if the vehicle is used for frequent towing without an external cooler. Using a robust synthetic transmission fluid that resists thermal breakdown can extend the life of the transmission components, preventing shifting issues that often plague high-mileage units.
Finally, while the Highlander is known for its durability, the cooling system components, such as the water pump and radiator, can be points of failure in higher-mileage vehicles. Ensuring the AMSOIL Passenger Car Antifreeze is fresh and free of corrosive deposits is essential to prevent premature failure of these parts. By adhering to a rigorous maintenance schedule with high-performance lubricants, owners can address these known vulnerabilities proactively, ensuring the vehicle remains a reliable and capable partner for years of family adventures.