21 MPG combined is not going to win any fuel efficiency awards, but it’s an acceptable figure for the 2016 Cadillac CT6 AWD with the 3.6L V6. This isn’t a car bought by someone hyper-focused on pinching pennies at the pump. The CT6 buyer wants a large, comfortable, American luxury sedan with available all-wheel drive, and understands that those attributes come at a cost, one that includes more frequent visits to the gas station than, say, a hybrid Camry.

City and highway performance

The EPA estimates of 18 MPG in the city and 27 MPG on the highway provide a clearer picture of the CT6’s fuel consumption patterns. That city figure reflects the realities of stop-and-go driving, compounded by the CT6’s substantial curb weight. The highway number, however, is more respectable and achievable, especially on long road trips where the smooth-shifting eight-speed automatic transmission can settle into its highest gear and the engine barely sips fuel. Highway fuel economy is a strong suit for this drivetrain, reflecting the CT6’s competency as a comfortable long-distance cruiser.

Annual fuel cost

According to the EPA, the estimated annual fuel cost for the 2016 Cadillac CT6 AWD 3.6L is $2,100. This figure is based on driving 15,000 miles per year and using national average fuel prices. It’s a helpful benchmark, but your personal fuel costs will vary depending on your driving habits, the type of driving you do (city vs. highway), and, of course, the ever-fluctuating price of gasoline. Consider it a ballpark figure for budgeting, but not a guaranteed annual expense.

Real-world expectations

While the EPA numbers offer a standardized comparison point, real-world fuel economy often diverges. CT6 owners report seeing figures close to the EPA estimates, especially when diligently employing fuel-saving driving techniques. Aggressive acceleration and frequent short trips will drag the MPG down considerably, while consistent highway driving at moderate speeds can sometimes exceed the 27 MPG estimate. The car’s trip computer provides real-time and average fuel economy data, allowing drivers to monitor their fuel consumption and adjust driving styles accordingly. Remember that all-wheel drive systems inherently reduce fuel economy, so expect a slight penalty compared to the rear-wheel drive model. If fuel economy is a higher priority, check out CT6 MPG across all years and consider other model years or the rear-wheel-drive option.

How it compares

Compared to its competitors, the 2016 Cadillac CT6 AWD 3.6L lands roughly in the middle of the pack. The BMW 535i xDrive from the same year, for example, also powered by a six-cylinder and equipped with all-wheel drive, achieves an EPA-estimated combined MPG of 23, slightly better than the CT6. The Mercedes-Benz E350 4MATIC, another direct competitor, is rated at 24 MPG combined. On the other end, the Audi A6 3.0T quattro manages a combined MPG of around 22. These small differences matter to some buyers in this segment, but the CT6’s value, interior space, and distinctive styling often outweigh a minor MPG deficit. For those considering other Cadillac models, all Cadillac fuel economy data can be found on our site.

Tips to maximize efficiency

The easiest way to improve fuel economy in the CT6 is to practice smooth acceleration and avoid hard braking. The 3.6L V6 is responsive, but unnecessary bursts of speed waste fuel. Instead, anticipate traffic flow and maintain a consistent speed whenever possible.

Ensure your tires are properly inflated. Underinflated tires create more rolling resistance, which reduces fuel efficiency. Check your tire pressure regularly and inflate them to the recommended pressure listed on the doorjamb sticker.

Reduce the weight you carry in the car. Extra cargo adds unnecessary load, forcing the engine to work harder. Remove any items you don’t need on a daily basis, especially heavy objects in the trunk.

Avoid extended idling. If you’re stopped for more than a minute or two, turn off the engine. Modern engines are designed to restart quickly and efficiently, and you’ll save fuel by avoiding prolonged idling.

Use cruise control on the highway to maintain a constant speed. This can help prevent unintentional acceleration and deceleration, which waste fuel. However, be mindful of traffic conditions and avoid using cruise control in heavy or unpredictable traffic.