23 MPG combined isn’t going to win any awards, but it’s a perfectly reasonable figure for a 2016 Mercedes-Benz E400. This isn’t a hybrid or an economy car; it’s a refined, powerful sedan or coupe designed for comfortable cruising and effortless performance. The typical E400 buyer prioritizes a smooth ride, a luxurious interior, and a responsive engine over squeezing every last mile from a gallon of fuel. They appreciate the prestige and image associated with the Mercedes-Benz brand, and they are willing to accept middling fuel economy as part of the package.

City and highway performance

The E400’s split of 20 MPG in the city and 29 MPG on the highway reflects its strengths. The 3.0L twin-turbo V6 provides ample low-end torque for confident acceleration from a standstill, but stop-and-go traffic inevitably takes its toll. On the open road, the E400 shines.

Its relaxed demeanor, aided by the smooth-shifting 7-speed automatic transmission, allows it to achieve respectable highway fuel economy during long journeys. The aerodynamic design and relatively low engine speeds at cruising speed also contribute to the good fuel economy.

Annual fuel cost

According to the EPA, the estimated annual fuel cost for the 2016 Mercedes-Benz E400 is $2,500. This figure is based on driving 15,000 miles per year and using the national average fuel price at the time of testing. Individual fuel costs may vary depending on driving habits, location, and fluctuations in gasoline prices. Expect to spend more if you predominantly drive in the city or have a lead foot. Those who primarily stick to the highway and drive conservatively may see slightly lower annual fuel expenses.

Real-world expectations

While the EPA figures provide a standardized benchmark, real-world fuel economy often differs. E400 owners often report slightly lower combined MPG than the official rating, typically ranging from 20 to 22 MPG. Factors such as aggressive driving, frequent short trips, and the use of air conditioning can contribute to reduced fuel efficiency. However, disciplined drivers who prioritize smooth acceleration and maintain consistent speeds can often achieve numbers closer to the EPA estimates, and may even exceed the highway MPG on longer trips.

How it compares

The 2016 E400’s fuel economy positions it in the middle of the pack compared to its competitors. For example, the BMW 535i, with its 3.0L inline-6, achieves a similar 20 MPG city and 30 MPG highway, making for a virtually identical combined rating. The Audi A6 3.0T, boasting a supercharged V6, also lands in the same ballpark. Buyers often cross-shop between these three German brands, so subtle differences in MPG may factor into the final purchase decision. Some buyers will also consider the slightly smaller C-Class sedan, which can deliver better fuel economy, but lacks the E400’s spaciousness and more mature ride. You can view E400 MPG across all years here, or find all Mercedes Benz fuel economy data for a broader view.

Tips to maximize efficiency

Use the E400’s “Eco” driving mode. This setting optimizes the engine and transmission for fuel efficiency by softening throttle response and shifting to higher gears sooner. It makes a noticeable difference in everyday driving, particularly in stop-and-go traffic.

Ensure your tires are properly inflated. Underinflated tires increase rolling resistance, which directly impacts fuel economy. Check your tire pressure regularly and inflate them to the recommended specifications listed on the driver’s side doorjamb.

Avoid unnecessary idling. If you’re stopped for more than a minute, turn off the engine. Modern engines are designed to restart quickly and efficiently, and idling consumes fuel without moving the car. This is especially important in the E400, as its larger engine burns more fuel even when stationary.

Use cruise control on the highway. Maintaining a consistent speed minimizes unnecessary acceleration and deceleration, improving fuel efficiency. The E400’s adaptive cruise control system can further enhance fuel economy by automatically adjusting the car’s speed to maintain a safe following distance.

Minimize carrying extra weight. Carrying unnecessary items in your trunk or backseat increases the vehicle’s overall weight, requiring the engine to work harder and consume more fuel. Remove any extra items you don’t need on a daily basis.