23 MPG combined is adequate fuel economy for the 2018 Mercedes-Benz E400 4matic. This car is built for effortless long-distance cruising and confident all-weather performance, and buyers in this segment prioritize a smooth, powerful engine, a luxurious interior, and a comfortable ride. The E400 delivers all three, making its middling MPG acceptable to its target demographic.

City and highway performance

The EPA estimates show the E400 4matic achieving 20 MPG in the city and 27 MPG on the highway. This difference reflects the engine’s characteristics. The turbocharged 3.0L V6, while potent, needs to work harder in stop-and-go traffic, resulting in lower fuel economy. On the open road, the 9-speed automatic transmission allows the engine to cruise at lower RPMs, boosting efficiency and allowing for relaxed, quiet travel.

While 20 MPG isn’t great, luxury car buyers often accept this in exchange for brisk acceleration and the effortless torque of a six-cylinder engine. The 27 MPG highway figure is more respectable, allowing for decent range on long trips. The 4matic all-wheel drive system also adds to the overall weight, slightly decreasing fuel economy compared to rear-wheel drive models.

Annual fuel cost

According to the EPA, the estimated annual fuel cost for the 2018 Mercedes-Benz E400 4matic is $2,500. This figure is based on driving 15,000 miles per year and using national average fuel prices.

Individual results will vary depending on driving habits, local fuel prices, and the percentage of city versus highway driving. Aggressive driving, frequent short trips, and consistently running premium fuel (which is recommended but not strictly required) will all increase this annual cost. While $2,500 sounds like a lot compared to a hybrid, many E400 buyers are willing to absorb that cost to enjoy the car’s other attributes.

Real-world expectations

While the EPA estimates provide a baseline, real-world fuel economy often differs. Achieving the EPA’s 27 MPG highway figure is possible on long, steady road trips, but expect lower numbers in mixed driving conditions. Urban commutes with frequent stops and starts will likely result in fuel economy closer to the 20 MPG city estimate, or even slightly lower. Many E400 4matic owners report average fuel economy in the 21-24 MPG range, which aligns reasonably well with the EPA’s combined rating. Driving style plays a significant role. More conservative drivers get closer to the EPA estimates, and more aggressive drivers see a noticeable dip.

How it compares

The E400’s fuel economy positions it in the middle of its competitive set. The BMW 540i xDrive, with a turbocharged inline-six, achieves a similar 23 MPG combined. The Audi A6 3.0T, offering comparable performance and luxury, also lands around 22-24 MPG. The Lexus GS 350, while not turbocharged, delivers slightly better fuel economy at 23 MPG combined, although its driving experience is less engaging than the E400.

Choosing the E400 isn’t primarily about saving money at the pump. It is about striking a balance between performance, luxury, and all-weather capability. For buyers exploring all Mercedes Benz fuel economy data, it’s important to consider other models, but for those specifically seeking the virtues of the E-Class, the E400 is a powerful option to consider. Buyers interested in comparing E400 MPG across all years can find a wealth of historical data online.

Tips to maximize efficiency

The E400’s 9-speed automatic transmission is designed to maximize fuel economy. Make sure to use “Comfort” mode for everyday driving. This mode encourages earlier upshifts and smoother acceleration, helping to keep the engine in its most efficient range. Avoid aggressive acceleration and hard braking, as these actions consume more fuel. Anticipating traffic flow and maintaining a steady speed can significantly improve your mileage.

Regularly check your tire pressure. Underinflated tires increase rolling resistance, which reduces fuel economy. Refer to the sticker on your driver’s side doorjamb for the recommended tire pressure, and ensure your tires are properly inflated. Even a few PSI below the recommended pressure can impact fuel efficiency.

Minimize unnecessary weight in the vehicle. Extra cargo adds to the car’s overall weight, requiring the engine to work harder and consume more fuel. Remove any items you don’t need, such as sporting equipment or tools, to lighten the load and improve gas mileage.

Consider using cruise control on long highway drives. Cruise control helps maintain a consistent speed, which can improve fuel economy compared to manually modulating the throttle. However, be mindful of hilly terrain, as cruise control may downshift frequently to maintain speed, negating some of the fuel-saving benefits.