23 MPG combined isn’t going to win any hypermiling awards, but for the 2015 Mercedes-Benz E350 Convertible, it’s a reasonable compromise. This isn’t a car designed for maximum fuel efficiency, it’s a stylish, open-air cruiser built for enjoying the journey. The target demographic, affluent individuals and couples who value luxury, performance, and the Mercedes-Benz brand, accept this fuel consumption as part of ownership.

City and highway performance

The EPA estimates provide a breakdown of 20 MPG in the city and 28 MPG on the highway. The city figure reflects urban driving, where the 3.5L V6 engine spends more time idling and accelerating. The highway number showcases the engine’s efficiency at steady cruising speeds, aided by the smooth-shifting 7-speed automatic transmission. These figures are important, but driving style and conditions significantly impact actual fuel consumption. Expect lower numbers with aggressive acceleration or in heavy traffic, and potentially higher numbers with careful driving on long, open stretches of road.

Annual fuel cost

The EPA estimates that the annual fuel cost for the 2015 Mercedes-Benz E350 Convertible is $2,500. This is based on driving 15,000 miles per year and using national average fuel prices. Premium fuel is recommended, which impacts this cost. This annual expense may not be a primary concern for the typical E350 Convertible buyer, but it’s still a factor to consider when budgeting.

Real-world expectations

While the EPA estimates provide a benchmark, real-world MPG will vary. Careful drivers may see numbers closer to the highway estimate during mixed driving, while those who frequently use the V6’s power will likely experience lower fuel economy. Road conditions, climate, and even tire pressure can play a role.

Consider the recommended premium fuel, and it becomes clear that the E350 Convertible is not the most economical choice for daily commuting. It’s better suited as a weekend or occasional use vehicle where fuel costs are secondary to the driving experience. See E350 MPG across all years to expand your research.

How it compares

Compared to its competitors, the 2015 E350 Convertible’s fuel economy is generally in line with other luxury convertibles of the era. For example, the BMW 435i Convertible (2015) with its turbocharged 3.0L inline-6 achieved around 25 MPG combined. The Audi A5 Cabriolet (2015) with its turbocharged 2.0L 4-cylinder was rated slightly higher at 27 MPG combined.

The choice often comes down to priorities. The Audi offers better fuel economy, but may lack the power and prestige of the Mercedes. The BMW offers a sportier driving experience, but its MPG is similar. The buyer choosing the E350 Convertible is often prioritizing the overall blend of Mercedes-Benz luxury, refined performance, and open-air driving exhilaration, accepting the fuel economy implications. View all Mercedes Benz fuel economy data for a wider perspective.

Tips to maximize efficiency

Take it easy on the accelerator. The E350 Convertible’s 3.5L V6 has ample power, but aggressive acceleration consumes significantly more fuel. Smooth, gradual acceleration will yield improvements in MPG. A gentle driving style and avoid jackrabbit starts whenever possible.

Maintain proper tire inflation. Underinflated tires increase rolling resistance, leading to reduced fuel efficiency. Check your tire pressures regularly and inflate them to the manufacturer’s recommended levels, typically found on a sticker inside the driver’s doorjamb. Properly inflated tires also improve handling and extend tire life.

Keep the car well-maintained. Regular servicing, including oil changes, air filter replacements, and spark plug inspections, ensures that the engine is running at peak efficiency. A neglected engine works harder and consumes more fuel. Stick to the recommended maintenance schedule outlined in the owner’s manual.

Minimize unnecessary weight. Carrying extra weight in the trunk or cabin reduces fuel economy. Remove any unnecessary items to lighten the load and improve MPG. This is particularly relevant for a convertible, where every pound can impact performance.

Use cruise control on the highway. Maintaining a consistent speed is more fuel-efficient than constantly speeding up and slowing down. When appropriate, engage cruise control on open roads to help optimize fuel consumption. Also, consider using the “Eco” driving mode if equipped to further optimize engine and transmission settings for economy.