The 2018 Cadillac XTS equipped with the 3.6L LF3-8 Twin-VCT engine is a sophisticated luxury sedan that demands precision maintenance to retain its smooth power delivery and reliability. Proper fluid selection is critical for this vehicle, particularly because of the high-output twin-turbocharged engine and the sensitive six-speed automatic transmission. Using high-quality synthetic lubricants helps mitigate heat degradation, protects against turbocharger wear, and ensures optimal fuel efficiency during daily commutes or long-distance travel. Below are the specific AMSOIL recommendations tailored to the technical requirements of this chassis.
Recommended AMSOIL Products
- AMSOIL Signature Series 5W-30 100% Synthetic Motor Oil – Delivers unsurpassed engine protection for up to 25,000 miles, offering 75% more protection against horsepower loss and wear caused by high RPMs and turbocharging.
- AMSOIL Extended-Life 5W-30 100% Synthetic Motor Oil – Provides extended protection for up to 20,000 miles with enhanced cleaning power to keep the high-pressure direct injection engine running smoother.
- AMSOIL OE 5W-30 100% Synthetic Motor Oil – A cost-effective option that exceeds GM Dexos1 Gen 3 specifications, specifically formulated to protect turbochargers and fight sludge.
- AMSOIL 5W-30 100% Synthetic High-Mileage Motor Oil – Ideal for engines with over 75,000 miles, featuring boosted detergents to clean the engine and reduced sludge.
- AMSOIL Oil Filter – Engineered for maximum filtration efficiency of 99% at 20 microns, capturing wear-causing contaminants better than standard filters.
- WIX XP Oil Filter – A premium option that offers improvements over original equipment manufacturer branded filters, providing superior protection for synthetic motor oils.
- WIX Oil Filter – A reliable choice that exceeds manufacturer OE recommended oil change intervals, offering protection against sludge and deposits.
- AMSOIL Passenger Car & Light Truck Antifreeze & Coolant – A unique OAT formulation providing protection up to 150,000 miles or 5 years, safeguarding the aluminum engine block and cooling system metals.
- AMSOIL Propylene Glycol Antifreeze and Engine Coolant – A concentrated option that offers protection up to 150,000 miles in passenger cars and light trucks, surpassing corrosion standards.
- AMSOIL Signature Series Fuel-Efficient 100% Synthetic Automatic Transmission Fluid – Designed to withstand the rigors of the 6T80 transmission, resisting thermal breakdown and maintaining fluidity in extreme temperatures.
- AMSOIL OE Fuel-Efficient 100% Synthetic Automatic Transmission Fluid – A cost-effective alternative that protects against wear and provides excellent lubrication for transmission components.
- AMSOIL SEVERE GEAR 75W-90 100% Synthetic Gear Lube – Essential for the rear differential with a Limited Slip Unit, containing friction modifiers to prevent chatter and control operating temperatures.
- AMSOIL DOT 3 and DOT 4 100% Synthetic Brake Fluid – Offers excellent ABS responsiveness and a stable viscosity range, ensuring consistent braking performance in all weather conditions.
When it comes to the 2018 Cadillac XTS 3.6L, the engine oil capacity is 7.0 quarts including the AMSOIL Oil Filter or WIX Oil Filter. After filling the system, it is crucial to check the oil level to ensure it is within the correct operating range. The engine requires a viscosity of 5W-30 for all temperature conditions. The oil drain plug should be torqued to 18 ft-lbs. The cooling system holds a significant volume of fluid, requiring approximately 10.4 quarts for a full flush and refill. Maintaining the correct AMSOIL Passenger Car & Light Truck Antifreeze & Coolant or AMSOIL Propylene Glycol Antifreeze and Engine Coolant mixture is vital for the longevity of the aluminum components in the cooling system and engine block.
Transmission maintenance is equally critical for this vehicle. The 6-speed 6T80 automatic transmission has a total fill capacity of 9.5 quarts, while the initial fill requires approximately 4.2 quarts. The actual capacity typically falls between 4.0 and 6.0 liters depending on the specific service performed. Using a synthetic transmission fluid like the AMSOIL Signature Series Fuel-Efficient 100% Synthetic Automatic Transmission Fluid ensures the torque converter and clutch packs receive adequate protection against heat, which can cause sludge buildup and premature wear. For the rear differential, the capacity varies slightly based on the presence of a Limited Slip Unit. If the unit has a CLU (Clutch Unit), the capacity is 1.5 pints; if it is without the CLU, the capacity is 1.3 pints. In either case, an LSD additive (GM P/N 88900330) is required to be added for optimal performance, specifically 0.05 liters or 1.69 oz.
About the 2018 Cadillac XTS
The 2018 Cadillac XTS represents the pinnacle of General Motors’ front-wheel-drive luxury platform, a chassis that has been the backbone of Cadillac’s sedan lineup for several years. Built on the GM Lambda platform, the XTS is designed to compete directly with European sedans in terms of comfort and technology, though it offers a more traditional, car-like driving feel rather than the aggressive handling of a sports sedan. It is a full-size luxury sedan that prioritizes a quiet, smooth, and comfortable ride, making it an ideal choice for executive transport and long highway journeys.
Under the hood lies the robust 3.6L LTG V6 engine, a twin-turbocharged powerhouse that delivers impressive torque and horsepower figures. This engine code LF3-8 is known for its responsiveness, though like many modern turbocharged engines, it places high thermal loads on the drivetrain during spirited driving. The interior is equally impressive, often featuring premium materials, a high-tech infotainment system, and a quiet cabin that effectively isolates passengers from road noise. The XTS is generally well-regarded for its spaciousness and the refinement of its ride quality, serving as a comfortable haven in traffic.
Despite its reliability reputation, the 2018 Cadillac XTS does face common issues that owners should be aware of. One frequent concern involves the electric power steering system, which can sometimes experience erratic behavior or a “stutter” feeling at low speeds. Another common problem is related to the engine’s turbocharger seals; over time, high heat can lead to oil leaking into the intake, causing the engine to consume oil or smoke. Additionally, some owners report issues with the engine coolant pump, where the impeller may separate from the shaft, leading to overheating. A fourth common area of concern is the transmission, which can develop shifting harshness or delayed engagement as the fluid ages and degrades under the stress of heavy loads.
These mechanical challenges highlight the importance of using superior lubricants. The high heat generated by the twin-turbo engine makes conventional oils susceptible to breaking down, which can accelerate wear on critical turbocharger components. By switching to 100% synthetic motor oils, owners can significantly reduce the risk of oil coking in the turbocharger bearings. Synthetic gear lubricants help maintain the friction properties required for limited-slip differentials, preventing the dreaded “chatter” that often plagues this vehicle. Furthermore, using high-quality brake fluid prevents moisture absorption, which is a leading cause of ABS module failure. Through proactive maintenance with premium fluids, the XTS can maintain its luxurious character and reliability for many years.
In conclusion, the 2018 Cadillac XTS is a capable and refined luxury sedan that rewards owners who prioritize high-quality maintenance. Whether you are driving in extreme cold or pushing the vehicle on a hot summer day, the correct fluids ensure that the sophisticated engineering of this car performs as intended. From the engine to the differential, every component benefits from the advanced chemistry found in AMSOIL synthetic products.