The 2018 Cadillac CTS equipped with the 3.6L V6 engine (Engine Code LF3 8) is a sophisticated machine that demands precision in its maintenance regimen. This vehicle, known for its responsive handling and powerful performance, houses a twin-turbocharged or naturally aspirated V6 that operates under high thermal and mechanical stress. To maintain the vehicle’s intended driving dynamics and ensure long-term reliability, the fluid selection must meet or exceed the strict specifications outlined by General Motors. Using standard mineral oils can lead to premature wear, sludge buildup, and reduced fuel efficiency, particularly given the engine’s sensitivity to oil viscosity and additive packages.
Recommended AMSOIL Products
For optimal protection and performance, the following AMSOIL products are specifically formulated for the 2018 Cadillac CTS 3.6L. These selections address the unique needs of the LF3 engine, the transmission, and the drivetrain components.
- AMSOIL Signature Series 5W-30 100% Synthetic Motor Oil – Provides the highest level of protection, outperforming industry standards and offering up to 25,000 miles of protection. It is ideal for drivers seeking maximum horsepower retention and wear protection in both extreme temperatures and heavy towing conditions.
- AMSOIL Extended-Life 5W-30 100% Synthetic Motor Oil – Offers a balance of performance and value with 20,000 miles of guaranteed protection. This oil features advanced cleaning power to help keep the engine running smoother for longer intervals.
- AMSOIL OE 5W-30 100% Synthetic Motor Oil – Designed to meet OEM mileage intervals with a formulation that fights sludge and deposits effectively, providing trusted protection for standard driving conditions.
- AMSOIL 5W-30 100% Synthetic High-Mileage Motor Oil – A specialized blend for vehicles with over 75,000 miles, featuring enhanced anti-wear additives and detergents to reduce sludge and improve overall engine health.
- AMSOIL Oil Filter – Delivers 99% filtration efficiency at 20 microns, offering superior capacity for contaminants compared to many competitors to help reduce engine wear.
- WIX XP Oil Filter – Features premium media that improves upon original equipment manufacturer (OEM) specifications, offering high filtration standards for the CTS.
- WIX Oil Filter – A reliable filtration choice for standard service intervals that removes contaminants effectively.
- AMSOIL Signature Series Fuel-Efficient 100% Synthetic Automatic Transmission Fluid – Withstands the rigors of heavy towing and elevated temperatures while remaining fluid in sub-zero conditions, providing reserve protection during high-stress driving.
- AMSOIL SEVERE GEAR® 75W-90 100% Synthetic Gear Lube – Essential for the limited-slip differential, this lube contains friction modifiers and controls thermal runaway to reduce operating temperatures and extend equipment life.
- AMSOIL Passenger Car & Light Truck Antifreeze & Coolant – A unique phosphate-, nitrate-, and silicate-free formulation that provides protection for up to 150,000 miles, safeguarding all cooling system metals and hoses.
- AMSOIL Propylene Glycol Antifreeze and Engine Coolant – A concentrated option that offers long-lasting protection for the cooling system in passenger cars and light trucks.
- AMSOIL DOT 3 and DOT 4 100% Synthetic Brake Fluid – Features excellent ABS and traction-control responsiveness with a stable viscosity over a wide temperature range to ensure consistent braking performance.
Engine Oil and Filter Specifications
The 3.6L LF3 engine in the 2018 Cadillac CTS requires a 5W-30 viscosity grade that meets the GM Dexos1 Gen 3 specification. The oil capacity for a complete change, including the filter, is 7.0 quarts. It is critical to check the oil level after refilling and to torque the drain plug to 18 ft/lbs. The engine’s turbocharged components, if equipped, and direct injection system benefit significantly from the superior thermal stability and anti-wear properties found in AMSOIL’s synthetic formulations.
AMSOIL oils are engineered to outperform conventional oils and even the specifications required by the manufacturer. The Signature Series, for example, has been tested to show 75% more engine protection against horsepower loss and wear. For owners looking for a budget-friendly option that still maintains synthetic quality, the OE line is a robust choice. Those with higher mileage should consider the High-Mileage formula, which helps reduce sludge by 67% and contains boosted detergent packages to clean existing deposits.
Pairing the correct oil with a high-quality filter is essential. The AMSOIL Oil Filter (EAO17) is designed with advanced media to trap contaminants while maintaining low oil restriction, ensuring parts remain lubricated even under high flow conditions. Alternatively, the WIX XP Oil Filter (WL10255XP) offers premium media that improves upon OEM-branded filters, while the standard WIX Oil Filter (WL10255) provides reliable filtration for conventional service intervals.
Transmission and Drivetrain Fluids
The 2018 CTS features an 8-speed automatic transmission requiring TL-80SN….WS fluid. A total fill for this transmission requires 11.9 quarts, while the initial refill capacity is approximately 5.5 quarts (though actual refill capacity can vary between 5.2 and 5.7 liters). Using a synthetic fluid like the AMSOIL Signature Series Fuel-Efficient Automatic Transmission Fluid ensures the transmission remains fluid in sub-zero temperatures and provides a reserve of protection during heavy use, such as towing or aggressive acceleration. For those preferring an OE specification equivalent, the AMSOIL OE Fuel-Efficient 100% Synthetic Automatic Transmission Fluid is also available.
The rear differential also requires specific attention. Depending on the configuration, the vehicle may have an ELSD clutch rear limited-slip differential or a standard differential. The ELSD clutch requires 0.2 pints, while the 226mm rear differential requires 2.5 pints, and the 195mm rear standard differential requires 1.9 pints. AMSOIL SEVERE GEAR® 75W-90 is the recommended lubricant for these applications. It contains friction modifiers specifically designed for limited-slip differentials, helping to control thermal runaway and protect against rust and corrosion, which is vital for maintaining the precision of the differential’s clutches.
Cooling and Brake Systems
Effective thermal management is crucial for the longevity of the Cadillac CTS’s high-performance engine. The cooling system has a capacity of 13.7 quarts for the engine and 1.7 quarts for the passenger car and light truck coolant reservoir. AMSOIL Passenger Car & Light Truck Antifreeze & Coolant (ANTPC) is a 50/50 pre-mix formulation that exceeds OEM requirements, offering protection for up to 150,000 miles. For those who prefer to mix their own coolant, the Propylene Glycol Antifreeze and Engine Coolant offers concentrated protection for up to 150,000 miles or 5 years in passenger vehicles.
The brake system on the CTS benefits from the use of AMSOIL DOT 3 and DOT 4 100% Synthetic Brake Fluid. Synthetic brake fluids have a higher boiling point than conventional glycol-based fluids, reducing the risk of brake fade under heavy braking. This fluid provides a stable viscosity across a wide temperature range, ensuring excellent responsiveness for the vehicle’s ABS and traction control systems.
Additional Maintenance and Care
For seasonal storage, the AMSOIL Gasoline Stabilizer can keep fuel fresh for up to 12 months, protecting against varnish and gum buildup caused by ethanol. The AMSOIL Engine Fogging Oil is an excellent rust preventive for internal engine components during long periods of inactivity. For regular driving, the AMSOIL P.i. Performance Improver is a highly recommended fuel additive that can restore up to 14% horsepower and clean fuel injectors to 100% flow rate after a single tank of fuel, particularly beneficial for GDI (Gasoline Direct Injection) engines where carbon buildup is a common issue. The AMSOIL Upper Cylinder Lubricant further complements this by lubricating the fuel system.
For vehicle cleaning and protection, a range of other AMSOIL products are available. The Miracle Wash Waterless Wash and Wax Spray allows for easy cleaning without water, leaving a protective shine. The Brake and Parts Cleaner effectively removes oil and grease from components. Exterior protection is handled by the Exterior Ceramic Spray or the Silicone Spray. Interior cleanliness is maintained with the Interior Detailer – Light Lemon or Interior Detailer – Scent Free. The Glass Cleaner cuts through grime without streaks. For heavy-duty cleaning needs, the Heavy-Duty Degreaser or Engine Degreaser work well. The Power Foam® Carburetor and Induction-System Cleaner helps remove carbon deposits. For undercarriage protection, the Heavy-Duty Metal Protector or MP Metal Protector can prevent corrosion. The Mudslinger® Mud and Dirt Repellent keeps ATVs and dirt bikes clean. General lubrication needs can be met with the Synthetic Multi-Purpose Grease.
About the Vehicle
The 2018 Cadillac CTS represents the pinnacle of the brand’s midsize luxury sedan offerings during that era. Part of the third generation (GM alpha platform), the CTS was designed to compete directly with the BMW 5 Series and the Mercedes-Benz E-Class. The vehicle is celebrated for its sharp, athletic handling, a trait that sets it apart from many of its luxury competitors which often prioritize a softer, more floating ride. The 3.6L V6 engine, available in both naturally aspirated and twin-turbocharged variants, delivers a robust balance of power and refinement. The naturally aspirated version produces around 335 horsepower, while the ATS-V CTS variant pushes significantly higher figures, though the 3.6L base engine itself provides spirited performance for daily driving and spirited canyon runs.
Owners of the 2018 CTS often appreciate its driver-focused cabin, which features high-quality materials and advanced technology, including the CUE infotainment system and available driver-assist technologies. The vehicle’s heritage is rooted in a lineage of performance-oriented Cadillacs, aiming to shed the image of being solely a boat-like cruiser and re-establishing the brand as a player in the enthusiast market. The LF3 engine family is known for its direct injection and variable valve timing, technologies that enhance efficiency but can require high-quality lubricants to manage the thermal loads associated with direct injection and turbocharging.
While the 2018 CTS is a reliable vehicle, certain issues can arise that are exacerbated by the use of inferior fluids. One common area of concern is oil consumption or carbon buildup on the intake valves, a known characteristic of direct injection engines. Using an oil with a strong detergent package like AMSOIL can help mitigate sludge formation and keep the valvetrain clean. Another potential problem is transmission shudder or harsh shifting, which can occur if the transmission fluid degrades or loses its frictional properties over time. Synthetic transmission fluid like the AMSOIL TL-80SN equivalent can extend the fluid’s life and maintain consistent shifting quality. Furthermore, the cooling system in high-performance engines can suffer from corrosion if the coolant becomes depleted or contaminated. A high-quality antifreeze like AMSOIL’s can prevent corrosion in the aluminum blocks and radiators, avoiding costly overheating repairs. Finally, brake fade under repeated hard stops is a risk in performance driving; the high boiling point of AMSOIL’s synthetic brake fluid ensures that the brake pedal remains firm and responsive, maintaining safety and control when the vehicle is pushed to its limits.