Diesels; they’re those engines used in big trucks and a lot of European cars, right?
To be honest, even as a motoring enthusiast, that was about the extent of my diesel expertise prior to writing this article. I knew that diesel engines took diesel fuel (duh) and powered many American commercial trucks. I also knew that diesels were popular among the British, who generally pay around $7 per gallon for gas or diesel, so prefer the latter for its increased efficiency.
Still, I had significant, embarrassing gaps in my knowledge:
- What’s the chemical difference between diesel and gasoline?
- Why aren’t diesel cars popular in America?
- What’s it like to drive a diesel?
- Will buying and owning a diesel save the average under-30 a noticeable amount of money?
To fill my knowledge gaps, I began a Top Gear-style investigation into this motoring phenomenon, though with fewer middle-aged British men falling down. Let’s start with the basics.
What’s the difference between diesel and gas?
In short, very little. Both forms of fuel create internal combustion, igniting inside your engine to drive pistons inside cylinders, creating rotary power through your crankshaft, eventually driving your wheels.
The chief difference comes in how the two types of fuel are ignited. Because traditional gas ignites at a high temperature, gasoline-powered engines need spark plugs to assist with ignition. Compression alone is enough to ignite diesel. Plus, since diesel is denser with energy, diesel engines are generally around 30% more efficient than gasoline engines and generate more low-end torque.
If diesel engines are torquier and more efficient than gasoline engines…
Why aren’t diesel cars popular in america?
Diesels have had a tough go in the States. For decades, most diesel engines couldn’t meet American emissions standards, so they gained the reputation of being “dirty” and were only desirable in trucks due to their high torque output.
By the 2010s, advancements in efficiency and polar-bear-friendliness meant that the average European diesel sedan could more easily pass U.S. emissions standards. As a result, foreign carmakers prepared to flood U.S. showrooms with delightfully diesel-sipping options.
The effort to “ignite” a diesel revolution in America, however, was spearheaded by Volkswagen. As you may recall, in 2015 VW Group were caught cheating on U.S. emissions testing and thus became the subject of environmental agencies’ scorn and scrutiny worldwide. The Teutonic titans suffered a significant blow to their brand and sales and dragged the reputation of diesels down with them. “We definitely pulled the plug for diesels here in this country,” lamented then-VW North American chief Hinrich Woebcken.
In 2017, Mercedes-Benz discontinued selling diesel cars in America. Both Dieselgate and the fact that fewer than 3% of their cars sold here were diesels surely played a role.
So, like the latest scandal-ridden celebrity, do diesels deserve to be shunned and shamed? Not at all; according to fueleconomy.gov, “new advances in diesel technology have improved performance, reduced engine noise and fuel odor, and decreased emissions of harmful air pollutants.”
Diesel trucks have always been popular, but for the 2018 model year there are several diesel-powered cars and SUVs to choose from.
- BMW 328d, 540d, X5 35d
- Chevrolet Cruze and Equinox
- Jaguar XE, XF, and F-Pace
- Land Rover Range Rover, Range Rover Velar, Range Rover Sport, and Discovery
- GMC Canyon and Terrain
- Jeep Grand Cherokee
- Mazda6 and CX-5
For the under-30 crowd, the Chevys and Mazdas are probably your best bet. The Cruze, Equinox, 6 and CX-5 are all dependable, nice to drive, and affordable to lease. Adding a diesel makes them all the more enticing.
More on cost differences in a bit. If you test drive a diesel, will anything feel different?
What’s it like to drive a diesel?
To find out, we asked Chevy to loan us the most millennial-friendly diesel there is: The fiercely-likable Cruze hatchback. Chevy’s oft-forgotten little hatch offers 47 cubic feet of cargo space, planted handling, stellar ergonomics, zippy acceleration, and an excellent infotainment system for well under $30k.
Though both the gas—and diesel—powered Cruzes accelerate to 60 in 8.4 seconds, the diesel is wildly more fun to drive. Because it produces nearly 100 lb-ft more torque than its gas brother, the diesel Cruze accelerates from 0-30 like a sports car before the power quickly tapers off. We’re fine with this, since most of our day is spent accelerating within this range, not all the way to 60 like we’re hoping to be cast in Fast and Furious.
Aside from a drastically different power curve, driving a diesel isn’t much different from driving a gas-powered car. Just be careful not to fill your diesel tank with gasoline, which in addition to causing engine damages leads to plumes of black smoke erupting from your tailpipes. Diesels don’t need additional bad publicity.
Now onto the main event. Diesels are fun and funky, but are they frugal?
Will buying and owning a diesel save you money?
Unlike in Europe, owning a diesel in America isn’t quite the fiscal no-brainer. Looking at the multiple dimensions of car ownership, we can see how things get muddled:
Price: Diesels typically cost between $2,500 and $4,000 more than their gas-powered counterparts, but they depreciate much more slowly.
Maintenance: Diesel engines have no spark plugs or distributors, so you’ll never have ignition-related tune-ups or repairs on your diesel (which could be $1,000-$3,000 in the life of a gasoline car). But, with fewer parts and labor available, diesels are generally more expensive to repair.
Insurance: Because parts, labor, and replacement costs are higher for diesels, insurance companies charge 10%-15% higher premiums to cover them. There’s no but here; it’s just bad news for diesel buyers.
Fuel: In America, a gallon of diesel hovers around 30-40 cents higher than a gallon of 87 octane. However, diesels do have a distinct advantage in fuel economy, usually around 20% higher than their gasoline-powered counterparts. The Cruze diesel we tested, for example, gets 30/45 city/highway compared to the gas version’s 28/37.
There’s an old anecdote that in America, a diesel takes five years to pay off its upfront premiums. With so many variable factors and different models it’s hard to verify for sure, but the figure sounds about right. Buying a diesel will not save you money; owning one might.
Who is a diesel for, then? In trucks, they’re an easy sell: High torque for towing and off-roading, and a flooded used market driving down prices. In cars and SUVs, however, they really only save you money if you drive 10k+ highway miles per year.
Why drive a diesel instead of a hybrid? Because your local dealer, desperate to get rid of his diesels, gives you a deal. Go investigate!