Maintaining the 2018 GMC Acadia equipped with the 3.6L LGX S engine requires attention to fluid quality and capacity specifications to ensure longevity and optimal performance. This engine is known for its smooth power delivery but benefits significantly from the use of synthetic lubricants that can withstand the thermal stresses of a turbocharged environment and the varying demands of family hauling. Using the correct oils and fluids not only preserves engine components but also helps maintain the vehicle’s fuel efficiency and responsiveness over time.
Recommended AMSOIL Products
- AMSOIL Signature Series 5W-30 100% Synthetic Motor Oil – Provides unsurpassed engine protection with up to 25,000 miles of service intervals, featuring superior wear resistance and horsepower retention.
- AMSOIL Extended-Life 5W-30 100% Synthetic Motor Oil – Offers 37% more cleaning power than OE oil and extends protection intervals to 20,000 miles for drivers seeking a balance of performance and value.
- AMSOIL Oil Filter – Engineered with high-capacity media to capture small contaminants, ensuring lower restriction and enhanced engine protection for the 3.6L engine.
- AMSOIL Passenger Car & Light Truck Antifreeze & Coolant – A ready-to-use 50/50 pre-mix that protects cooling system metals and lasts up to 150,000 miles or 5 years.
- AMSOIL Signature Series Fuel-Efficient 100% Synthetic Automatic Transmission Fluid – Designed to withstand heavy towing and elevated temperatures while maintaining fluidity in sub-zero conditions.
- AMSOIL SEVERE GEAR® 75W-90 100% Synthetic Gear Lube – Delivers advanced protection against wear and thermal runaway in rear differentials with limited-slip components.
The heart of the 2018 GMC Acadia is the 3.6L LGX S V6 engine. This naturally aspirated powerplant delivers a robust blend of power and efficiency, typically producing around 310 horsepower. For owners who enjoy this SUV, it is essential to understand the specific fluid requirements to keep this engine running at peak performance. The engine oil capacity for the 3.6L LGX S is approximately 6.0 quarts when changing the oil filter. It is crucial to refill the correct amount and then check the oil level after the refill to ensure proper lubrication of all moving parts. The vehicle requires an oil grade that meets the GM Dexos 1 Gen 3 specification, a standard that emphasizes low-speed pre-ignition (LSPI) protection, which is vital for direct-injection turbocharged and direct-injection engines to prevent damaging carbon buildup and component wear.
When selecting a motor oil, AMSOIL Signature Series 5W-30 100% Synthetic Motor Oil stands out as the premier choice. This full synthetic formulation contains a high concentration of high-quality base stocks and advanced additive packages that provide 75% more engine protection against horsepower loss and wear compared to standard oils. This level of protection is critical for the 3.6L engine, which operates under significant thermal loads. For those who prefer a slightly longer interval between changes, the AMSOIL Extended-Life 5W-30 100% Synthetic Motor Oil is an excellent alternative. It offers 20,000 miles of guaranteed protection and includes enhanced cleaning detergents to combat sludge formation, keeping the engine cleaner over the long term. The AMSOIL OE 5W-30 100% Synthetic Motor Oil is another strong contender, formulated to outperform conventional oils and specifically fight the sludge and deposits that can plague higher-mileage vehicles.
Filter selection is equally important. The AMSOIL Oil Filter is rated to filter with 99% efficiency at 20 microns, which means it captures far more of the harmful particulates that cause wear than standard filters. It also features a greater capacity for small contaminants, reducing the restriction and keeping the engine lubricated more effectively. Alternatively, the WIX XP Oil Filter is a premium option that offers improvements over original equipment manufacturer-branded filters, ensuring that synthetic oil is not compromised by low-quality filtration media.
Beyond the engine, the automatic transmission in the 2018 Acadia, identified as the 6T70, requires specific attention. A total fill of this transmission holds approximately 9.5 quarts. Standard fluids can break down under the stress of heavy towing, elevated temperatures, and challenging terrain, leading to sluggish shifts and potential transmission failure. AMSOIL Signature Series Fuel-Efficient 100% Synthetic Automatic Transmission Fluid is formulated to withstand these rigors while providing excellent resistance to oxidation and wear. It remains fluid in sub-zero temperatures, ensuring smooth operation even in cold weather, and provides reserve protection during heavy use. The AMSOIL OE Fuel-Efficient 100% Synthetic Automatic Transmission Fluid offers a cost-effective alternative that still provides significant protection against wear and helps maintain optimal fuel economy.
The cooling system of the Acadia is another area where synthetic fluids can make a difference. With AC, the system holds approximately 12 quarts of AMSOIL Passenger Car & Light Truck Antifreeze & Coolant, while models without AC hold around 11.1 quarts. This antifreeze is an ethylene glycol, 50/50 pre-mix that is compatible with all cooling system metals, gaskets, and hoses. It is free of phosphates, nitrates, and silicates, making it safe for extended use without damaging seals or causing corrosion. For those who prefer mixing their own, the AMSOIL Propylene Glycol Antifreeze and Engine Coolant provides a non-toxic alternative that offers protection up to 150,000 miles or 5 years.
Finally, the rear differential and power steering system require regular maintenance to ensure smooth operation. The rear differential holds approximately 1.7 pints of lubricant. AMSOIL SEVERE GEAR 75W-90 100% Synthetic Gear Lube is ideal for this application, as it controls thermal runaway and protects against rust and corrosion. It also contains friction modifiers specifically designed for limited-slip differentials. For the power steering system, AMSOIL 100% Synthetic Multi-Vehicle Power Steering Fluid helps seals remain soft to prevent leaks, resists heat for a long fluid life, and provides strong anti-wear protection. Additionally, the AMSOIL DOT 3 and DOT 4 100% Synthetic Brake Fluid recommendation ensures excellent ABS and traction-control responsiveness by maintaining a stable viscosity over a wide temperature range.
About the Vehicle
The 2018 GMC Acadia represents a significant milestone in the history of General Motors’ mid-size SUVs. Positioned as a direct competitor to vehicles like the Ford Explorer and the Toyota Highlander, the Acadia offers a blend of family-friendly utility and crossover-style handling. Produced at the GM Lansing Delta Township plant in Michigan, this generation of the Acadia is built on the GM Sigma II platform, which shares roots with the Chevrolet Traverse. The platform was designed to maximize interior space, offering three rows of seating that can accommodate up to seven or eight passengers depending on the trim and configuration. This makes it a popular choice for large families, carpooling groups, and those who need to transport significant cargo.
Under the hood, the 2018 model year is notable for the transition to the 3.6L V6 engine across most trims, including the S, SLE, SLT, and Denali. The 3.6L LGX engine is a modern iteration of GM’s family of high-performance V6s, offering a balance of power that makes merging and highway passing effortless. Owners typically appreciate the smooth power delivery and the relative quietness of the cabin, which has been engineered to minimize road and wind noise. The suspension system, often equipped with the available Magnetic Ride Control in higher trims, provides a comfortable ride that can also handle spirited driving when the road opens up. Inside, the Acadia features a modernized interior with updated technology, including an 8-inch diagonal color touchscreen with GMC Pro Safety and the IntelliLink infotainment system, which allows for seamless smartphone integration.
Despite its strengths, the 2018 GMC Acadia 3.6L has faced some specific challenges that owners and mechanics have identified over the years. Proper lubrication with high-quality synthetic fluids can help mitigate several of these issues. One common problem involves sludge formation in the engine, particularly if the vehicle has undergone stop-and-go driving or has not had regular oil changes. The use of AMSOIL’s extended-life oils, which contain superior detergent packages, can help dissolve existing sludge and prevent new deposits from forming, keeping the variable valve timing system clean and functional.
Another area of concern is the potential for coolant leaks, often originating from the water pump or thermostat housing, which are common failure points on the 3.6L engine. While replacing the faulty gasket is the primary repair, using a high-quality antifreeze like AMSOIL Propylene Glycol Antifreeze and Engine Coolant can provide better corrosion inhibition and thermal stability, potentially extending the life of the cooling system components. Additionally, some owners report transmission shift shocks or harshness, especially in colder climates or under heavy load. This is often due to the degradation of the transmission fluid over time. Regularly changing to a premium synthetic automatic transmission fluid can restore smooth shifting characteristics and protect the torque converter and clutch packs from premature wear.
Finally, the rear differential in some 2018 models can experience issues with limited-slip clutch wear, leading to whining noises during turns. This is often exacerbated by the breakdown of standard gear oil under heavy towing conditions. Switching to a 100% synthetic gear lube like AMSOIL SEVERE GEAR 75W-90 100% Synthetic Gear Lube can significantly reduce operating temperatures and provide the necessary friction modifiers to keep the limited-slip clutch engaging smoothly, preventing the noise and wear that can affect ride quality. By addressing these specific areas with the right fluids, owners can extend the service life of their 2018 GMC Acadia and ensure it remains a reliable and comfortable vehicle for years to come.
In conclusion, the 2018 GMC Acadia is a capable and versatile SUV that rewards attentive maintenance. By utilizing the recommended AMSOIL fluids and filters, owners can enjoy the full potential of this vehicle, from the engine’s power output to the smooth operation of the transmission and differential. The comprehensive range of synthetic products available ensures that every component of the Acadia receives the protection it needs, whether navigating city streets or hauling cargo on a long road trip.