Maintaining the optimal performance of your 2016 Cadillac CT6 begins with selecting the correct lubricants for its sophisticated 3.6L LGX S engine. As a flagship luxury sedan, the CT6 demands precision fluid compatibility to ensure smooth operation, fuel efficiency, and long-term reliability. AMSOIL synthetic lubricants are formulated to exceed the vehicle’s original equipment manufacturer requirements, providing superior protection against the wear and heat generated by the high-performance direct-injection system. Whether you are navigating city traffic or cruising on the highway, the right oils and filters are essential for keeping the engine clean and the transmission responsive.
Recommended AMSOIL Products
- AMSOIL Signature Series 5W-30 100% Synthetic Motor Oil – Offers unsurpassed engine protection against horsepower loss and wear, extending service intervals up to 25,000 miles or one year.
- AMSOIL Extended-Life 5W-30 100% Synthetic Motor Oil – Provides 20,000 miles of guaranteed protection with enhanced cleaning power to help keep the engine running smoother and longer.
- AMSOIL OE 5W-30 100% Synthetic Motor Oil – A trusted option that outperforms conventional oils, protecting turbochargers effectively and fighting sludge with a 100% synthetic formulation.
- AMSOIL 5W-30 100% Synthetic High-Mileage Motor Oil – Specifically designed for vehicles with over 75,000 miles, featuring boosted detergents to reduce sludge and enhance engine cleanliness.
- AMSOIL Oil Filter – Delivers 99 percent filtration efficiency at 20 microns, offering greater capacity for contaminants and lower restriction to keep engine parts lubricated.
- AMSOIL Passenger Car & Light Truck Antifreeze & Coolant – A pre-mixed, phosphate- and silicate-free solution that protects cooling system metals, gaskets, and hoses up to 150,000 miles.
- AMSOIL Propylene Glycol Antifreeze and Engine Coolant – A concentrated option that surpasses standards for metallic corrosion and erosion, offering protection up to 150,000 miles or five years.
- AMSOIL Signature Series Fuel-Efficient 100% Synthetic Automatic Transmission Fluid – Withstands heavy towing and elevated temperatures while remaining fluid in sub-zero conditions for the 8L45 transmission.
- AMSOIL SEVERE GEAR® 75W-90 100% Synthetic Gear Lube – Provides advanced protection against wear and thermal runaway for the differential, including limited-slip applications.
- AMSOIL DOT 3 and DOT 4 100% Synthetic Brake Fluid – Ensures excellent ABS and traction-control responsiveness with a stable viscosity across a wide temperature range.
Engine Oil Specifications and Capacities
The 2016 Cadillac CT6 equipped with the 3.6L 6-cylinder engine (Engine Code [S] LGX S) requires a specific motor oil grade to meet GM Dexos 1 Gen 3 specifications. The engine oil capacity is 6.0 quarts when a filter change is performed. When refilling, it is crucial to check the oil level to ensure the proper quantity is maintained. The drain plug torque specification is 18 ft/lbs to prevent leaks or damage during the service.
For drivers seeking maximum performance, the AMSOIL Signature Series 5W-30 is the premier choice. This synthetic blend offers 75% more engine protection against horsepower loss and wear compared to industry standards. Its formulation is designed to guard against the specific stressors of modern turbocharged and direct-injection engines. Alternatively, the AMSOIL Extended-Life 5W-30 provides 20,000 miles of protection, making it an excellent option for those who prefer slightly longer intervals while maintaining superior cleaning power.
For owners of vehicles with higher mileage, the AMSOIL 5W-30 High-Mileage Motor Oil features a unique chemistry with boosted detergents to help reduce sludge by 67%. This ensures that older engines continue to perform better and last longer. The AMSOIL OE 5W-30 is another robust option that is trusted by professional engine builders and protects against Low-Speed Pre-Ignition (LSPI) events effectively.
To complete the oil change process, the AMSOIL Oil Filter is recommended. It provides a high level of filtration efficiency while allowing lower restriction, which keeps critical engine parts lubricated even during high-flow operations. This filter helps reduce engine wear and offers extended service life to match the longevity of the synthetic oil.
Cooling and Antifreeze Recommendations
Proper cooling system maintenance is vital for the longevity of the CT6’s engine. The cooling system capacity varies depending on the specific radiator configuration. For vehicles equipped with the RAC10 radiator, the total capacity is 10.4 quarts. For those with the RAC12 radiator, the capacity increases to 12 quarts. Using the correct antifreeze ensures that the cooling system metals, gaskets, and hoses are protected against corrosion and freezing.
For convenience and optimal protection, the AMSOIL Passenger Car & Light Truck Antifreeze & Coolant is a 50/50 pre-mixed formulation that requires no dilution. This Ethylene Glycol-based coolant protects the engine in temperatures as low as -34°F and as high as the boiling point of the fluid. It is phosphate-, nitrate-, and silicate-free, making it compatible with a wide variety of cooling system components. For those who prefer a concentrated option, the AMSOIL Propylene Glycol Antifreeze offers exceptional thermal stability and corrosion protection, surpassing OEM requirements for long-term engine health.
Transmission and Differential Lubrication
The automatic transmission in the 2016 Cadillac CT6 is the 8-speed 8L45 model. Proper lubrication is critical to handle the demands of heavy towing, elevated temperatures, and challenging terrain. The total fill capacity for the 8-speed transmission with a cooler is 11.4 quarts, while the fill without a cooler is 10.9 quarts. An initial fill requires 7.4 quarts. The AMSOIL Signature Series Fuel-Efficient 100% Synthetic Automatic Transmission Fluid is formulated to withstand the rigors of heavy use while providing reserve protection during abusive conditions.
The differential lubrication requirements depend on the specific axle configuration. For the front differential (SL146), the capacity is 1.1 pints. The rear differential varies slightly by the specific unit; the 200 mm rear unit holds 1.1 pints, while the 225 mm rear unit holds 2.3 pints. For all differential applications, the AMSOIL SEVERE GEAR® 75W-90 is the recommended lubricant. It contains friction modifiers for limited-slip applications and helps control thermal runaway, ensuring long oil life and reduced operating temperatures.
Other Fluids and Maintenance
Brake fluid plays a crucial role in the safety and responsiveness of the CT6. The recommended fluid is a DOT 3 hydraulic brake fluid. The AMSOIL DOT 3 and DOT 4 100% Synthetic Brake Fluid provides excellent ABS and traction-control responsiveness while maintaining stable viscosity over a wide temperature range.
For owners who use seasonal storage or want to maximize fuel efficiency, the AMSOIL Gasoline Stabilizer helps keep fuel fresh for up to 12 months, protecting against varnish and ethanol corrosion. Additionally, the AMSOIL P.i.® Performance Improver restores up to 14% horsepower and cleans GDI fuel injectors to 100% flow rate after a single tank of fuel, improving overall fuel economy and preventing carbon buildup.
Vehicle Background
The 2016 Cadillac CT6 represents a significant moment in the brand’s history, marking the debut of a new flagship sedan designed to compete with the top European luxury sedans. Built on the GM Alpha platform, the CT6 features a lightweight aluminum-intensive structure that contributes to its dynamic driving character and handling precision. The vehicle was engineered to offer a sophisticated blend of luxury, technology, and performance, positioning it as a top-tier competitor in the full-size luxury segment.
The 3.6L V-6 engine paired with the eight-speed automatic transmission provides a smooth and powerful driving experience, delivering ample horsepower while maintaining reasonable fuel economy for a vehicle of its class. Owners of the CT6 appreciate its spacious interior, advanced infotainment system, and a ride quality that balances comfort with sporty agility. The platform’s engineering allows for a wide range of engine options, but the naturally aspirated V-6 remains a popular choice for its reliability and smooth power delivery. As a flagship model, the CT6 serves as a showcase for Cadillac’s latest technological innovations and design language, making it a standout choice for those seeking a modern, high-performance luxury sedan.