22 MPG combined is not the main reason someone buys a 2018 Cadillac XTS with the 3.6L V6. This car focuses on traditional American luxury: a smooth ride, a spacious interior, and understated elegance. Fuel economy is a secondary concern. The XTS buyer values comfort and size over efficiency, prioritizing a plush ride and a quiet cabin for long highway trips or transporting clients. They are likely downsizing from an even larger sedan or upgrading from something less luxurious, and accepting the fuel consumption as a trade-off for the Cadillac experience.

City and highway performance

The XTS gets 19 MPG in the city, a number that reflects the car’s weight and the engine’s need to work harder in stop-and-go traffic. Expect this figure to dip further with aggressive driving or excessive idling. On the open road, the XTS fares better, achieving 28 MPG on the highway. The six-speed automatic transmission helps keep the engine in its optimal range at cruising speeds, contributing to the improved highway fuel economy. Consistent highway driving is where the XTS can come closest to meeting its EPA estimates; city driving will almost certainly result in lower numbers.

Annual fuel cost

The EPA estimates the annual fuel cost for the 2018 Cadillac XTS 3.6L at $2,000. This figure is based on driving 15,000 miles per year, with 55% of those miles driven in the city and 45% on the highway, using the EPA’s combined MPG rating and assuming national average fuel prices. Actual costs can vary depending on driving habits, local fuel prices, and the type of fuel used.

Real-world expectations

While the EPA numbers provide a baseline, actual fuel economy can be significantly different. XTS owners often report figures that are slightly below the official estimates, especially in mixed driving conditions. Aggressive acceleration, frequent short trips, and prolonged idling can all negatively impact fuel economy. Those who primarily use the XTS for highway travel may see numbers closer to, or even slightly above, the 28 MPG highway estimate, but overall, expect the combined MPG to hover around 20-22 MPG in everyday use.

How it compares

Compared to other large sedans of its era, the 2018 Cadillac XTS’s fuel economy is about average. The Buick LaCrosse, which shares a similar platform and engine, achieves comparable MPG numbers. A Lexus ES 350 of the same year, while smaller, offers significantly better fuel economy, around 26 MPG combined. A Lincoln Continental with its optional 3.0L twin-turbo V6 sacrifices fuel economy for more power, achieving around 19 MPG combined. These comparisons matter to the XTS buyer because they highlight the compromises in choosing a large, traditionally luxurious sedan: more space and comfort come at the expense of fuel efficiency. For a full view of all Cadillac fuel economy data, including the XTS MPG across all years, FuelEconomyHub provides detailed information.

Tips to maximize efficiency

Gentle acceleration is key to maximizing fuel economy in the XTS. Avoid aggressive starts and hard braking, as these consume more fuel. Smooth, gradual acceleration allows the engine to operate more efficiently and reduces unnecessary fuel consumption.

Ensure your tires are properly inflated. Underinflated tires increase rolling resistance, forcing the engine to work harder and reducing fuel economy. Check your tire pressure regularly and inflate them to the recommended pressure listed on the driver’s side doorjamb.

Reduce unnecessary weight in the vehicle. Extra cargo adds to the car’s overall weight, which in turn requires more fuel to move. Remove any items you don’t need to carry regularly, such as sporting equipment or heavy tools.

Minimize idling time. Letting the engine idle for extended periods consumes fuel without moving the car. If you’re stopped for more than a minute, it’s generally more fuel-efficient to turn off the engine and restart it when you’re ready to go. This is particularly relevant in city driving.

Consider using cruise control on the highway. Cruise control helps maintain a consistent speed, which can improve fuel economy. However, avoid using cruise control in hilly terrain, as the system may cause the engine to work harder to maintain speed, negating any potential fuel savings.