23 MPG combined might not sound like much, but for the 2015 Mercedes-Benz E350 4matic with its reliable 3.5L V6, it’s a reasonable compromise. This isn’t a car bought for hypermiling; it’s a car bought for effortless power, all-weather confidence thanks to its 4MATIC all-wheel drive, and the understated luxury that the E-Class has always offered. The fuel economy simply comes with the package.

City and highway performance

The E350 4matic earns its EPA estimates with a naturally aspirated V6. The 20 MPG city rating reflects the engine’s need to work harder in stop-and-go traffic. It’s a decent number, but not class-leading. However, the 27 MPG highway figure shines. This is where the Mercedes-Benz excels, swallowing up long distances with ease and returning acceptable fuel economy while doing so. The smooth-shifting seven-speed automatic transmission also contributes to highway efficiency, keeping the engine in its sweet spot for cruising.

Annual fuel cost

The EPA estimates the annual fuel cost for the 2015 Mercedes-Benz E350 4matic at $2,500. This figure is based on driving 15,000 miles per year and using national average fuel prices for premium gasoline, which this engine requires for optimal performance. Keep in mind that your actual fuel costs will vary depending on your driving habits, fuel prices in your area, and how often you drive. If you live in an area with high fuel costs or drive aggressively, you can expect to spend more than $2,500 per year on gasoline.

Real-world expectations

While the EPA estimates are a good starting point, understanding real-world expectations is important. Most owners report that achieving the EPA’s 27 MPG highway estimate is entirely possible with careful driving. However, the city figure of 20 MPG is often optimistic. Many drivers report closer to 17-18 MPG in true city driving conditions. The combined figure of 23 MPG is achievable for those who split their time evenly between city and highway. The E350, especially with 4MATIC, is not at its best in dense urban environments with frequent stops and starts. The engine’s weight and all-wheel-drive system add to the fuel consumption in those conditions.

How it compares

Compared to its rivals, the 2015 E350 4matic sits in the middle of the pack. The BMW 535i xDrive of the same year, for example, rated at 22 MPG combined, 19 city, and 29 highway, offers slightly better highway fuel economy but a similar city MPG. The Audi A6 3.0T quattro, another all-wheel-drive competitor, achieves near identical numbers, emphasizing the similarity of the German luxury sedan set. The Cadillac CTS 3.6L AWD, with its slightly more aggressive tuning, comes in with 19 MPG combined. Buyers of this level of vehicle accept these numbers as the price for performance and all-weather capability. Those prioritizing less gas often look at hybrid alternatives, such as the Lexus ES 300h, which delivers significantly better fuel economy (40 MPG combined) but sacrifices the driving dynamics and prestige associated with the E-Class. Comparing E350 MPG across all years is useful for seeing where the 2015 model stands in the E-Class’s history.

Tips to maximize efficiency

Maintain proper tire inflation. The E350’s tire pressure monitoring system (TPMS) is a helpful tool, but periodically check the pressures manually. Properly inflated tires reduce rolling resistance, improving fuel economy noticeably, especially on long trips. Consult the sticker on your driver’s side door jamb for the recommended pressure.

Smooth and steady acceleration is key. The V6 engine delivers ample torque, so avoid aggressive launches and heavy braking. Gentle acceleration and anticipation of traffic flow will not only save fuel but also reduce wear and tear on your brakes and tires. Remember, a heavy foot wastes gas.

Limit idling. Modern engines are surprisingly efficient when running, but idling consumes fuel without covering any distance. If you anticipate being stopped for more than a minute, such as at a long traffic light or waiting for someone, consider turning off the engine. It might seem small, but the cumulative effect over time can be significant.

Use cruise control on the highway. Cruise control helps maintain a constant speed, minimizing fluctuations that can reduce fuel economy. While the adaptive cruise control found in some higher trims is even better, standard cruise control is still a valuable tool for saving fuel on long highway drives. Set it and forget it, allowing the car to maintain speed efficiently.

Keep up with scheduled maintenance. Regular oil changes, air filter replacements, and spark plug maintenance are essential for optimal engine performance and fuel efficiency. A well-maintained engine runs more smoothly and efficiently, maximizing the energy from each gallon of fuel. Be sure to follow the Mercedes-Benz recommended maintenance schedule found in your owner’s manual or consult with all Mercedes Benz fuel economy data to compare service intervals.