Diesel vs Gas: Which Is Better?

The biggest difference between diesel vs gas engines, of course, is that they use different types of fuel. Diesel engines run on diesel or biodiesel. They rely on compression to ignite fuel rather than a gas engine’s spark plugs. They are also more fuel-efficient than gas engines. Gas engines, on the other hand, run on gasoline or a blend of gasoline and ethanol. They are less fuel-efficient but many gas engines today are quite efficient. Here are three more keys ways in which gas and diesel engines differ:

Diesels produce more torque at lower RPMs and from a complete stop. That’s why they’re better than gas engines for towing or hauling heavy loads. Gas engines produce more power than diesels at high RPM, which is why many sportscars are powered by gasoline engines.

Ignition happens faster with a gas engine, which are less temperamental in cold weather than diesels. Diesels will start in the cold, but they may need a block heater and an additive to prevent the fuel from gelling.

Gas is easier to find than diesel fuel, and it’s cheaper, too. However, you will get better milage with a diesel. Modern diesels in the U.S. also rely on an additive called DEF that cuts down on their emissions. Depending on the type of vehicle, you may need to use more or less DEF for every tank of fuel you burn.

Table of Contents

• How Diesel and Gas Engines Work
• Diesel vs. Gas Cost Savings
• Life Expectancy of Gas vs Diesel Engines
• Diesel vs Gas: Cool Factor
• Diesel vs Gas: Headache Factor
• Diesel vs. Gas: How to Choose the Right Engine

Both diesel engines and gas engines use internal combustion for power, but diesel engines use compression to ignite the fuel. Most modern diesels utilize fuel injection to get diesel to the cylinders. Once its there, a piston compresses the fuel under a lot of pressure. The heat generated from this ignites the fuel and starts the process over again. As mentioned, modern diesels also use an additive called DEF to nuetralize the exhaust and convert harmful nitrogen oxide to nitrogen and water.

Gasoline engines use spark plugs to ignite fuel once it reaches the cylinder. When your car starts, gasoline is in injected into the cylinder where it is compressed and mixed with air against a spark plug. The plug is powered by your car’s battery, and when it sparks, it causes an explosion in the cylinder that drives a piston and powers the engine. Gasoline engines have devices to mitigate the exhaust they produce, but they do not require any separate additives.

Diesel vs. Gas: Cost Savings

If you want to buy a diesel, you’re going to have to shell out more upfront. Diesel trucks and cars cost on average $5,000 to $10,000 more than their gas-powered counterparts. Maintenance on a diesel will usually cost more, too. Because of their complicated exhaust systems, diesels can require more trips to the mechanic, and if you’re towing with one, it will put more wear and tear on your vehicle.

You will save money on oil changes with a diesel, though. Oil on a diesel doesn’t need to be changed as frequently as it does on a gas engine. Diesel engines also last longer than gas engines. Where you might want to trade in your gas-powered car at 100,000 miles, a diesel is just getting broken in. This, and a few other things, make the resale value of diesel higher, so you’ll get more money back when you are ready to sell.

Finally, diesel does cost a bit more than gas at the pump, but diesels are more fuel efficient. This really comes into play if you’re towing. My diesel truck will average 16-18 miles to the gallon towing a 20-foot trailer. A gas engine may only break 10 miles to the gallon doing the same thing. To figure out how much you’d save on a diesel vs. gas engine, you really need to look into cost savings that relate specifically to the way you drive. The upfront, maintenance, and fuel costs of diesel might be justified if you plan on towing and covering a lot of highway miles. So, when it comes to diesel vs gas cost savings, it’s kind of a toss-up.

Diesel engines last a lot longer than gas engines because they generate power at lower RPMs. In other words, diesels don’t need to turn over as frequently as gas engines and less turning over means a longer life. Older diesel trucks with no emission systems can last almost indefinitely with proper maintenance. It isn’t uncommon to see a diesel with more than 300,000 miles on the clock still purring like a cat. The clear winner for longevity is diesel.

This depends on what circles you run in, but in the working-pick-up-truck world the diesel is king. Afterall, diesels are what real truckers use. It says that you not only have a pick-up, you get things done with your pick-up. As a matter of fact, there are a few other worlds where diesels are pretty damn cool, too. Broke college professor driving a diesel Mercedes from the 80s? Yup, that’s about as cool as he’s going to get. How about a soccer mom in a European diesel minivan? She’s getting points with from other parents who wish they could justify a Duramax. Diesels are just a bit different, and in America, being a little different is still cool. This one goes to diesel.

Diesel vs. Gas: Headache Factor

I’ve owned diesel trucks and cars ever since I got my license. My family runs a bus and trucking outfit, and they’ve run diesel trucks forever. One thing I can say is that diesels can be no fun when they’re not working. Parts are expensive, and now with emission regulations, you have complex mechanical systems to maintain. Like all complex mechanical systems, they tend to break and cost a lot of money when they do.

There’s also the fact that sometimes you can’t find diesel to save your life. I’ve white-knuckled it with my tank on E for a lot miles in search of diesel, only to find more and more gas. And if you do have the misfortune of running your diesel out of fuel, it will need to be primed before it can start again. Diesel also has trouble in the cold. Every winter, I need to put fuel additives in my diesel tank otherwise my truck wont start.

All of this, of course, is just the price of being cool (think of how long it took Elvis to style his hair everyday). But in terms of how much of a pain-in-the-ass a vehicle can be, gasoline engines are a lot more user friendly than diesels.

Style aside, this decision completely hinges upon how you drive. It’s also getting more difficult to find diesel vehicles in the U.S., and pretty soon you might not be able to make the choice. When it comes down to it, those who tow a lot or carry heavy loads should consider a diesel. Older diesels are also pretty apocalypse proof if that sort of thing matters to you. (They can even be converted to run on fuel made from vegetable oil.) If you have a long commute, you might want to look into a smaller diesel-powered car or van. These are uncommon in the U.S. but are very popular in Europe because of their fuel efficiency.

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For the rest of you, go with a gas engine—even if you’re driving a pick-up and tow occasionally. For the outdoorsman, gas engines and gas-powered trucks are lighter and better off road than a diesel. You also won’t have the emission headaches that come with a diesel. Though DEF is pretty easy to find, it can be a pain to keep up with. Mechanics are more familiar with gas engines, too, so you’ll have an easy time finding someone to maintain it. And even though gas engines are less fuel efficient, they are way more fuel efficient than they used to be.