Besting Highway MPG In A Luxury Diesel Sedan
Recently, we were able to get behind the wheel of a 2015 Mercedes-Benz E250 and do some real world mileage testing. Our week of seat time consisted of start-stop daily commuting on the streets and freeway of the L.A. suburbs. We also found the time for some steady state freeway and desert back road cruising as well.
By most accounts, the Mercedes-Benz E-class sedan is considered to be in the Mid-Size Luxury class. Essentially, this means that it’s more upscale than entry-level four-door cars, with more bells and whistles, while being smaller in scale than a full-size sedan. By our count, there are seven sedans in this class, but only three that are currently available with a diesel engine.
The E250 has an impressive array of standard features, in keeping with it being a luxury class sedan. A few of these on the safety side are radar-based autonomous braking, and cruise control that steers and brakes.
Of these three diesel-powered offerings, the MB E250 is the only one with a fuel-sipping 2.1L four-cylinder diesel. While not as powerful as the competitor’s V-6 oil burners on paper, we didn’t feel a lack of power when driving the E250. The smaller 2.1L engine allows the E250 to offer up an EPA rating that has a 2- to 4-gallon city advantage over the two diesel-powered competitors and a 4-mpg highway advantage over both. In fact, the E250 has come to the market with a best in class EPA rating of 28/42. The initial info released by Mercedes-Benz on the E250 estimated a highway mpg of 45 highway, and while the EPA downgraded this to only 42 hwy, we were able to get long stretches that showed 45 mpg or more on the flats.
The E250 has an impressive array of standard features, in keeping with it being a luxury class sedan. A few of these on the safety side are radar-based autonomous braking, and cruise control that steers and brakes. The autonomous braking kicks in above 5 mph and uses “multirange radar” to check your speed and distance in comparison to the vehicle in front of you. Get too close, and you’ll get an alert to brake; ignore it and the E250 will brake for you. Also, when in cruise, the Steering Assist feature will help to keep you in your lane, even around mild curves.
While the 2.1L BlueTEC diesel engine is small and easy on fuel, it’s more powerful than some V-8s on the road. The twin turbos act in unison to provide quick response at low speed and rpm, while still offering up top end power when the as the larger turbo comes into play.
The interior of the E250 is modern and full of conveniences. After slipping into the quite-comfortable front seat, we immediately noticed the 14-way power adjustments, lumbar support and other comforts. Better still, the E250 has a three-position memory for the driver’s seat. This allows you to store your favorite settings for seat position as well as the steering column and side mirrors, for yourself and two other drivers.
Perhaps the one thing that bothered us the most was the lack of a spare tire, or rather the lack of notification of a spare tire. We found that the early owner’s manual neglected to state that the E250 came with all-season run-flat tires, as the DEF tank took up the space normally used for a spare tire in the gas-powered models. Admittedly, the sales brochure did cover this and we’re sure the dealer would too. On the upside, the 17-inch run-flats rode well.
Overall, we were quite pleased with the E250 for comfort, conveniences and most of all for the little fuel-sipping diesel. The EPA rating of 42 highway and a fuel capacity of 21.1 gallons means a highway range of well more than 800 miles. This is about the distance from Los Angeles to El Paso, Texas, or a third of the way across the USA. DW
THE EPA and Mileage Ratings
The EPA rates mileage on cars and light trucks in three categories: city, highway and combined. The testing that gathers this information tends to favor gas-powered vehicle, and it’s not uncommon for owners of diesel vehicles to get better than the EPA numbers, especially when driving with a light foot. In addition, diesel engines tend to get better mileage after a break-in period. Since the EPA testing is done on a “new” vehicle, diesels are disadvantaged during testing. This is because they’re at their best after engine break-in.
The 2015 Mercedes-Benz E250 has an EPA rating of 28/42 mpg. To most of us, this would suggest an average of 35 mpg. However, the EPA average is rated at 33 mpg. It seems that the EPA feels that the average driver spends more time on city driving so they weight these numbers. The average mpg rating is based on 55 percent of the time in the city and 45 percent of the time on the highway. As a result, all EPA average city/highway mpg number ratings are rounded down. The spread between the two is rounded down by 2 mpg, when the difference is 1.5 mpg or greater. This is why the EPA average for the 2015 E250 is only 33 mpg. Go to www.FuelEconomy.gov for mileage numbers and comparisons.
E250 Clean Diesel Stats
2.1L I-4 Twin-Turbo
Power: 195 hp @ 3,800 rpm
Acceleration: 0-60 mph in 7.9 sec (Optional 4MATIC: 8.2 sec)
City fuel economy: 28 mpg (Optional 4MATIC: 27 mpg)
Highway fuel economy: 42 mpg (Optional 4MATIC: 38 mpg)