The Top 5 Most Fuel Efficient Diesel Cars

If you want to save money at the pump, the best diesel cars can save you hundreds of dollars a year over their gasoline counterparts.

The reason extends beyond which fuel hose is selected at the gas station. For starters, the internal architecture of the engines is significantly different.

“When it comes to traversing great distances at highway speeds, the diesel engine’s higher compression ratios and lean-burn combustion provide an efficiency that no gas engine can currently match – at least not without a major assist from an expensive hybrid system,” explained Popular Mechanics.

Combining this effective setup with diesel fuel, which produces more energy by volume than gasoline, and you get an engine with 15 percent more thermodynamic efficiency than a gasoline engine.

This translates to substantial savings at the pump. As an example, the 2015 BMW X5 sDrive35d (with a 3.0-liter turbo diesel engine, pictured above) gets an average of 27 mpg. In comparison, the gasoline-powered sDrive35i, powered by a 3.0-liter turbo, is rated at 22 mph.

The EPA estimates that the diesel BMW will save $550 in fuel expenses every year (on average). It can travel more than 100 miles further on a tank of fuel than its gas-only sibling, and emits 1,000 fewer pounds of greenhouse gas emissions annually. It should also be noted, though, that the diesel X5 costs about $3,800 more to purchase and will carry higher maintenance costs over its lifespan.

Because finding the best diesel cars for sale often starts with the models that will save you the most in fuel every year, we’ve put together a list of the 2015 Top 5 Most Fuel Efficient Diesel Cars.

2015 Volkswagen Golf SportWagen Diesel

Combined fuel rating: 35 mpg

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2015 Volkswagen Golf SportsWagen

If there’s one area that Volkswagen outshines, it’s with the diesel engine. About half of all diesel cars sold in the U.S. last year came from this German carmaker. And though the Golf SportWagen isn’t in the top five for sales, it is one of the most economical diesel cars to buy.

The wagon’s 2.0-liter turbo diesel engine is rated an average of 35 mpg with either transmission option, though the manual 6-speed gets a slightly higher highway rating (43 mpg) over the automatic 6-speed (42 mpg).

Coming in just behind the Golf SportWagen is one of the most popular diesel cars, the Volkswagen Passat Diesel. The sedan is routinely posted near the top of the diesel car sales tallies. Though its overall 35 mpg is equal to the number five pick (and its 44 mpg highway rating is just above), the Passat’s 30 mpg in the city brings down its fuel efficiency slightly. Still, this Volkswagen diesel deserves an honorable mention.

2015 Volkswagen Golf Diesel

Combined fuel rating: 36 mpg

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2015 Volkswagen Golf Diesel

A foot shorter and a little lower to the ground than the wagon above, the Volkswagen Golf Diesel also weighs 120 pounds less. This helps give the hatchback gain little bit of an advantage in fuel economy for an overall rating of 36 mpg.

Powering the Golf is the same 2.0-liter turbo diesel engine as the Golf SportWagen, with the transmission options trading places for efficiency. The automatic six-speed has a slight edge, with a rating of 43 mph highway/31 mpg city (versus 45 highway/30 city for the manual transmission).

2015 Audi A3 Diesel

Combined fuel rating: 36 mpg

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2015 Audi A3

Tying for third place with the Golf Diesel is the 2015 Audi A3 Diesel. It also uses a 2.0-liter turbo diesel engine, and gets the exact same fuel rating as the Golf (36 mpg combined/43 mpg highway/31 mpg city). Both even have the same power output of 150 horsepower. The A3 diesel, though, is only available with an automatic transmission.

While the Golf is a zippy hatchback, the A3 built to be a sophisticated sedan. As a member of the luxury class, the Audi comes with a tag that can reach as high as $10,000 over the Golf’s $20,000ish price. This may partly account why the A3 trails the Golf in sales. Either way, the A3 and the Golf offer excellent diesel fuel savings in fun to-drive-packages.

SEE ALSO: Government Forecasts Low Gas & Diesel Prices Through 2016

2015 Volkswagen Jetta Diesel

Combined fuel rating: 36

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2015 Volkswagen Jetta Diesel

It may appear the 2015 Volkswagen Jetta is merely continuing the trend of 36 mpg combined ratings, but the fuel advantages of this sedan are discernible by looking at the details.

When paired with a manual transmission, the Jetta’s 2.0-liter turbo diesel delivers a category-leading 46 mpg on the highway. The automatic six-speed comes in just under at 45 mpg. Both are rated at 31 mpg in the city.

With more models topping both the list of bestselling diesel cars and the list of the most fuel efficient diesel cars than any other automaker, it certainly seems Volkswagen has found a successful formula for its diesels.

2015 BMW 328d Diesel

Combined fuel rating: 37 mpg

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2014 BMW 328d

The 2015 BMW 328d is the only diesel car this year to achieve 37 mpg combined. It’s also the only car with a 32 mpg city rating, and its highway rating of 45 mpg is one of the best.

The 328d is only available as a 2.0-liter turbo diesel with an 8-speed transmission. A lack of options doesn’t limit performance, though, with fuel efficient tuning that doesn’t diminish power. In fact, the 328d not only gets a higher fuel rating that the other diesel cars on our list, but it’s also more powerful with a 180-horsepower rating.

The 328d is also available as the slightly faster 328 xDrive Sedan or the larger 328d xDrive Sports Wagon, both with 35 mpg combined diesel fuel ratings.