21 MPG combined isn’t going to win any awards in 2017, but it’s a compromise for the 4.7L twin-turbo V8 under the hood of the Mercedes-Benz CLS550. This isn’t a car for hypermilers; it’s for drivers who value effortless power and a certain style. The CLS550 buyer appreciates a beautifully sculpted four-door coupe with a potent engine, and fuel economy is a secondary consideration, though not entirely ignored. They likely have other, more efficient vehicles in the garage, or the means to absorb the fuel costs.

City and highway performance

The Mercedes-Benz CLS550 delivers an EPA-estimated 18 MPG in the city. This figure reflects stop-and-go traffic, where the powerful V8 accelerates the car’s weight frequently. On the open highway, however, the CLS550 demonstrates its grand touring capabilities, achieving 26 MPG. The smooth-shifting 9-speed automatic transmission helps, keeping the engine in its most efficient operating range when cruising at higher speeds. This difference between city and highway fuel economy highlights the CLS550’s strength as a long-distance cruiser, where its comfort and performance can be fully appreciated.

Annual fuel cost

The EPA estimates that the annual fuel cost for the 2017 Mercedes-Benz CLS550 will be $2,750. This figure is based on driving 15,000 miles per year, with a mix of city and highway driving, and assumes national average fuel prices. It’s a useful benchmark for comparing running costs with other vehicles, but individual expenses may vary depending on driving habits and local fuel prices. The $2,750 annual cost is a direct consequence of the V8 engine’s thirst, a cost accepted by buyers who prioritize performance and prestige over efficiency.

Real-world expectations

While the EPA figures provide a standardized benchmark, real-world fuel economy can often change. Aggressive driving, frequent short trips, and extended idling will all negatively impact fuel consumption. Gentle acceleration, consistent highway speeds, and proactive maintenance can help approach or even exceed the EPA estimates. For CLS550 owners, who likely appreciate the car’s performance capabilities, achieving the EPA-rated 21 MPG combined will require a conscious effort to drive efficiently.

How it compares

Compared to its competitors, the CLS550’s fuel economy is expected for vehicles in its class. For example, the 2017 BMW 550i xDrive, another performance-oriented sedan with a V8 engine, achieves a similar 19 MPG city and 26 MPG highway. The Audi A7 3.0T Quattro, with its supercharged V6, offers slightly better fuel economy at 21 MPG city and 29 MPG highway, a reflection of its smaller, albeit still potent, engine. Buyers often cross-shop these vehicles, weighing the trade-offs between power, fuel efficiency, and brand cachet, and can compare all Mercedes Benz fuel economy data on this site.

Tips to maximize efficiency

Smooth and gradual acceleration can significantly improve fuel economy in the CLS550. Avoid sudden bursts of speed and allow the turbochargers to spool up gradually. This will help keep the engine operating in a more efficient range, reducing unnecessary fuel consumption. The CLS550 MPG across all years is relatively consistent, adapting smoother driving habits can help owners of all model years of this car save money.

Regular maintenance, including timely oil changes and air filter replacements, is important for optimal fuel efficiency. A well-maintained engine runs more smoothly and efficiently, minimizing friction and maximizing combustion, and consistent maintenance is key to maximizing the CLS550’s fuel economy over its lifespan.

Ensure that your tires are properly inflated. Underinflated tires increase rolling resistance, forcing the engine to work harder and consume more fuel. Check your tire pressure regularly, using the recommended inflation pressure listed on the driver’s side door jamb.

Consider using the CLS550’s “Eco” driving mode, if equipped. This mode typically adjusts throttle response, shift points, and other parameters to prioritize fuel efficiency. While it might slightly reduce performance, it can make a noticeable difference in fuel consumption, particularly in stop-and-go traffic.