Asking the Question: Comparing Diesel vs Gasoline Vehicles

When you pull into a gas station to fuel up your car, you’ve probably seen a special pump for diesel drivers. Sometimes, it’s an extra handle attached to the same machine; other times, it’s a completely separate pump that seems to be reserved for large semi-trucks. You’re likely familiar with this mysterious part of the station. However, if you haven’t been a truck driver up to this point, it probably hasn’t affected your life too much, even if you may have been a little bit curious about it.

But, if you’re now looking at used trucks for sale, you may be seeing some gas options and some diesel options. This can, justifiably, raise some questions about the differences between the two and which one is better. Like most things, there is not a cut-and-dry answer as to which one is objectively “better.” However, there are key differences between the two, and understanding the differences can help guide your shopping as you consider how you’ll be using your vehicle and what your driving habits are likely to be. Let’s start by hashing out the difference between the two fuel types.

Gasoline vs Diesel Fuel

First of all, what is gasoline, and what is diesel? Obviously, they are both different types of fuel, but what is the actual difference? Great question! Gasoline and diesel are similar, as they are both petroleum products derived from crude oil. A key difference, however, is that gas is more refined than diesel. As such, diesel is a thicker fuel, meaning it contains more energy per unit than gasoline. 

When it comes to the way these different fuel types interact with the engine itself, the end result is similar in that they both use internal combustion to drive the pistons, moving your truck forward. However, the cause of the combustion is where the process differs. Gasoline requires more carefully controlled ignition, so gasoline engines rely on a spark plug to ignite the air-fuel mixture; this causes a contained explosion, setting the pistons in motion.

Diesel, however, can simply be compressed until it ignites, eliminating the need for spark plugs. As such, diesel engines are known as compression combustion engines and do not include spark plugs but rather allow the diesel fuel to self-combust. As you can imagine, using the wrong type of fuel in a gas or diesel engine will cause significant problems. So, that’s the difference between the fuel types and the engines. But what are the benefits of each one for you personally? 

Different Types of Efficiency

One of the things you’ll often hear about when it comes to comparing diesel and gasoline trucks is fuel efficiency. However, it is a bit of a tricky question, as it really depends on the type of driving you’ll be doing and what you’re looking to achieve. 

If you’ve seen one of the aforementioned diesel pumps at your local gas station, you may have noticed that diesel is typically more expensive than gas. But while it does cost a little bit more upfront to fill your tank with this thicker fuel, its energy density causes it to provide more miles per gallon.

One thing to consider is whether you’re going to be driving more on the highway or in the city. While diesel is not necessarily less efficient in the city, you will likely see a bigger difference compared to a gasoline truck if most of your driving is going to be on the highway. It may take you longer to break even with fuel savings if you’re driving in the city, while highway driving will have faster results. 

At the end of the day, diesel engines are known to be more efficient due to the fuel having more energy per gallon, translating into more miles per gallon. If you’re willing to pay a higher price upfront, you could experience significant savings over time.

Horsepower vs Torque

Diesel engines and gas engines do provide differences in terms of power output, and it’s not necessarily as simple as “this one provides more power than the other.” It truly depends on what type of power you are trying to achieve. Diesel provides much more torque than gasoline, while gasoline provides a higher horsepower rating than diesel.

Most truck owners need towing and cargo-hauling capability. If that’s the case for you, diesel will likely be a better way to go. If you are looking for a used truck to haul trailers long distances, that’s a perfect candidate for a diesel engine. That said, if you are going to be driving in the city and are looking for a high-speed, horsepower-oriented vehicle, gas may be the better pick. You could think of diesel as a worker’s fuel; if you’re trying to put your truck to work and get the most energy per unit of fuel, diesel will serve you better. 

Maintenance Considerations

With any vehicle you consider, it’s always important to look into factors that could affect ease of maintenance. It’s easy to get caught up in the excitement of having all of the features you want in a used truck, but it is important to consider what it would realistically look like for you if you need significant maintenance. 

When it comes to maintenance considerations for diesel and gasoline engines, it is a two-sided argument. The first side is that diesel engines are likely to be more durable and should need less maintenance over time. Due to the compression combustion process, diesel engines operate at a higher level of thermal efficiency, meaning the engine does not get as hot, leading to less wear and tear over time. So, a diesel engine will likely have less need for maintenance than a gas engine. 

The flip side is that most auto shops and mechanics are well-equipped to handle gasoline engines, as they are far more common than diesel engines. Now, that is a shop-by-shop factor; if you have a mechanic who knows a lot about diesel engines and is ready to work on them, then that is not an issue. However, it is important to consider that diesel engines may have some higher maintenance costs attached to them, given that they operate using compression combustion, and certain parts like fuel filters and emissions control systems can be more expensive.

Crunching the Numbers

Diesel and gas each have their own pros and cons. It’s not a one-size-fits-all answer where one can say that diesel is better than gas or the other way around. Diesel provides greater efficiency with more miles per gallon, but gas is typically cheaper per gallon. Diesel provides higher torque ratings, but gas typically provides higher horsepower ratings. Diesel engines have greater durability and longevity due to their robust construction, but gas engines are usually easier and cheaper to repair.

With pros and cons to each engine type, the best way to approach the question is to consider what type of driving you’ll be doing. If you’re going to be crushing a lot of miles over time and need high torque to pull heavy trailers, the answer may be diesel. However, gasoline is often better suited to your average truck owner for its familiar nature. When you look at the value proposition of diesel, it does have the potential to provide significant fuel savings, longer engine life, and high torque ratings. If those are things that you think will be beneficial to you in a used truck, then you may want to consider switching to diesel.