The most fuel-efficient diesel-powered mid-sized sedan in the United States is the 2014 Mercedes-Benz E250 BlueTEC, which has received an EPA grade of 45 mpg highway in its rear-wheel-drive configuration. Now, it’s true that there really aren’t that many mid-size sedans that rely on diesel power in this country, and that the 2014 Mazda Mazda6 with its SKYACTIV-D powertrain has been delayed here, but the 2014 Mercedes-Benz E250 BlueTEC does offer a notable advantage against its top Teutonic rivals, as shown by the EPA ratings for these automatically transmissioned entries:
- 2014 Mercedes-Benz E250 BlueTEC—28 mpg city/45 mpg highway/34 mpg combined
- 2014 BMW 535d—26/38/30
- 2014 Audi A6 TDI—24/38/29
On the other hand, there are also a couple of caveats here. For one, the Audi A6 has the brand’s quattro all-wheel-drive technology standard; the 2014 Mercedes-Benz E250 BlueTEC slips to an EPA line of 27/42/32 with M-B’s 4matic all-wheel-drive setup. An even bigger difference is under the hood, where both the Audi and BMW showcase 3.0-liter V6 engines. In contrast, the E250 BlueTEC relies on a 2.1-liter 4-cylinder unit, creating a noticeable disparity in terms of output. While the M-B entry can deliver 195 hp and 369 lb-ft of torque, the BMW packs 255/413 and the Audi serves up 240/428.
Of course, on the other other hand—and admitting it may not be top of mind for premium customers—the 2014 Mercedes-Benz E250 BlueTEC is priced from $51,400 to give it a cost benefit of $6,100 against the A6 and $5,200 as compared to the 535d.