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Are you in the market for a new vehicle? If so, one of the factors that will influence your purchasing decision is the kind of engine that the vehicle has — gasoline or diesel. Diesel engines used to be found only in larger pickup trucks and tractor-trailers, but modern automotive technology has enabled diesel engines to be placed in vehicles of all sizes. So, is a vehicle that runs on diesel the right choice for you? We've done the research to bring you some concrete answers.
You might consider buying a diesel vehicle if you frequently tow heavy trailers or if engine longevity is of utmost importance to you. Aside from these scenarios, there is not a compelling case to buy a diesel vehicle, as the drawbacks that come with owning a diesel vehicle usually outweigh the benefits.
In this article, we are going to talk in-depth about the pros and cons of diesel engines to help you make a more educated decision with your car purchase. We will also talk about how alternative options like hybrid vehicles compared to diesel vehicles.
Diesel Buying Price
Price is understandably the most significant factor to evaluate when considering purchasing any vehicle. In the case of diesel engines versus gasoline engines, the difference in buying price can be considerable, depending on the vehicle.
Take a look at the 2019 Ford F150. The cost to upgrade from the standard gasoline engine to the diesel engine is $3,000. Believe it or not, this price difference is relatively low compared to the price difference of a diesel engine with other manufacturers.
Check out the 2019 Chevrolet Cruze. The cost to upgrade from the standard gasoline engine to the diesel engine is $5,375.
Another example is the 2019 Chevrolet Colorado. The difference in price from the V6 gasoline engine to the diesel engine is $5,430.
With heavy-duty trucks, the cost to upgrade to the diesel engine is staggering. In the case of the 2019 Ram 2500, the price difference between the gasoline and diesel engines is a whopping $9,100.
These examples demonstrate that it is safe to assume that the cost of a vehicle with a diesel engine will cost anywhere from $3,000 to $9,000 more than their counterparts with gasoline engines. The upfront cost of diesel vehicles is by far their biggest con.
Diesel Engine Performance
Performance is another factor to consider when purchasing a vehicle. For simplicity, we will evaluate a vehicle's performance based on its horsepower and torque specifications.
Take a look at the 2019 Chevrolet Colorado. The gasoline V6 engine produces 308 horsepower and 275 pound-feet of torque. The diesel engine produces 181 horsepower and 369 pound-feet of torque.
The 2019 Chevrolet Cruze with the gasoline engine produces 153 horsepower and 177 pound-feet of torque. Its diesel counterpart produces 137 horsepower and 240 pound-feet of torque.
The common theme is that gasoline engines generally boast of more horsepower than diesel engines, whereas diesel engines provide more torque. What does this mean, exactly? To put it directly, gasoline engines generally have more pep, but diesel engines produce more pulling power. In this sense, the performance difference is something of a tradeoff depending on the way the vehicle will be used.
The higher torque output from diesel engines has long been one of their most significant selling points. But given the advent of electric motors in modern vehicles, this diesel benefit is less compelling.
Vehicles that are entirely electric offer torque that is just as impressive as that of most diesel engines. Torque from entirely electric vehicles is available instantaneously, a performance benefit that gives the diesel a run for its money.
Some manufacturers have started integrating electric motors into their gasoline vehicles. Ram is a good example. Its new Etorque system provides additional low-end torque to supplement that produced by the gasoline engine. It is technically not a hybrid vehicle, but it makes use of electric power to give the truck more instantaneous torque.
In short, electric automotive technology has mostly closed the performance gap between diesel engines and other vehicle platforms.
Fuel Economy And Fuel Cost
Fuel economy is another factor to consider when purchasing a vehicle. In this category, diesel is the winner.
In the case of the 2019 Chevrolet Colorado, the diesel engine averages 2-3 more miles per gallon than the gasoline engine. Generally speaking, diesel engines are more fuel-efficient across the board. This proves especially true when towing.
The downside, however, is that historically, the average cost of diesel has almost always been higher than the average price of gasoline. Depending on the vehicle, this can negate the benefit of better fuel economy. In other words, a slightly better fuel economy might not be beneficial depending on the cost of diesel versus the price of gasoline.
Superior Fuel Economy with Hybrid Vehicles
Hybrid vehicles are worth mentioning here, as they boast of the best fuel economy on the market. For example, the Toyota Prius can average over 50 miles per gallon.
This is important to point out because it highlights the reality that, while diesel vehicles often have better fuel economy than gasoline vehicles, this difference is dwarfed in comparison to hybrid alternatives on the market.
Diesel vehicles have long had a reputation for polluting the environment more than vehicles that run on gasoline. Diesel vehicles likely got this reputation due to the black soot and pungent smell produced by burning diesel.
However, this reputation is not grounded in reality, especially with modern diesel engines. Burning diesel emits more particulate matter than gasoline does, but diesel emits significantly less carbon monoxide, hydrocarbons, and carbon dioxide than gasoline.
The primary reason for this is that modern diesel vehicles must meet strict emissions requirements. The primary way they do so is with something called diesel exhaust fluid (DEF). DEF is a liquid that is designed to break down harmful pollutants in the exhaust that is produced from burning diesel. It is stored in a separate tank from the diesel itself, and it is continuously sprayed into the exhaust stream.
These emissions requirements have led to the creation of modern diesel vehicles that are more environmentally friendly than their gasoline counterparts.
So, in terms of environmental pollutants, diesel is, without a doubt, more environmentally friendly than gasoline.
The Environmental Footprint of Hybrid vs. Diesel Vehicles
If a low environmental footprint is important to you in your car buying decision, you are likely also considering hybrid vehicles. Are diesel vehicles more environmentally friendly than hybrid vehicles? Well, not really.
Hybrid vehicles have much lower emissions because they sometimes run on an electric motor. While this may make them seem like an option that is environmentally superior to the diesel, it is essential to remember that the process of creating the electricity that powers the hybrid motor emits pollution. Compare that to the super clean modern diesel with virtually nonexistent harmful emissions, and the diesel is the winner in this category.
Maintenance And Cost of Maintenance
Diesel vehicles, just like all other vehicles, require maintenance to run correctly and efficiently. However, when it comes to maintenance, diesel vehicles are notorious for being particularly costly. While diesel engines are not necessarily known for having more issues than gasoline engines, when maintenance and repairs need to be done, they are generally much more expensive. We will go over some of the most common maintenance items that are more expensive with diesel vehicles.
One example is an oil change. Generally speaking, diesel engines require more oil than gasoline engines. For example, the Ram 1500 with the EcoDiesel engine requires 10.5 quarts of oil, whereas its gasoline counterpart only requires 7. While this might seem like a small difference, the costs associated with this simple, routine maintenance certainly add up over time.
Diesel Exhaust Fluid
Another example of routine maintenance that is worth mentioning is the requirement for diesel exhaust fluid (DEF) that we mentioned earlier. Most modern diesel vehicles will not operate without a sufficient level of DEF in the DEF tank. DEF is depleted relatively slowly, and it is relatively inexpensive, but it is another added cost that, in due time, will start to add up.
The DEF system can also be a headache for diesel vehicle owners. It is just another system that has the potential to fail, and when it does, it can be expensive to fix.
Fuel injectors in diesel engines are a regular maintenance item that is particularly costly. According to Repair Pal, the average cost to replace one diesel fuel injector is between $240 and $491. Compared to the cost of replacing spark plugs in a gasoline vehicle, this figure is staggering. If multiple fuel injectors fail, the repair can cost well over $1,000.
Diesel Engines Require Different Treatment
On the subject of maintenance, it is essential to point out that diesel vehicles require different treatment than gasoline engines.
Have you ever seen a cord sticking out close to the grille of a diesel vehicle? That cord is connected to something called a block heater. In cold conditions, the block heater, when plugged into a power source, keeps the engine's glow plugs at a high enough temperature to ignite the diesel when the engine is started. This is needed because diesel tends to become gel-like when it is frigid, making it more difficult to burn.
So what does this mean for you? It means that, if you live in a cold climate, you will have to plug your vehicle's block heater into a power source if you intend to let the vehicle sit for a while. If you do not, your diesel engine will likely have trouble starting.
One of the things that are unique to modern diesel vehicles is something called the regeneration process. Modern diesel vehicles are equipped with something called the diesel particulate filter (DPF). The DPF is located inside the exhaust system, and it helps filter out harmful particulates that are produced in the combustion of diesel.
The DPF has to undergo a regeneration process every so often. This process cleans the DPF by burning off carbon buildup in the system. There are three different ways that the regeneration process can happen —passively, actively, or forced. The specifics behind each of these regeneration processes will not be covered in this article, but you can click here to read more about the different processes from AutoGuru.
In short, a diesel engine and the exhaust must reach an unusually high temperature to burn off this carbon buildup and complete the regeneration process. If the vehicle sees frequent and long highway trips, the regeneration process happens naturally.
If the vehicle is only used for shorter trips, the engine might not be able to get hot enough to burn off the carbon successfully. The vehicle will then heat the engine abnormally by consuming excess fuel. During this time, if the vehicle drops below a certain speed or RPM, the engine can be damaged.
In sum, diesel vehicles must be treated differently than gasoline vehicles. This is one of the biggest pitfalls of modern diesel vehicles.
One of the categories in which diesel engines are superior is engine longevity. One of the most significant selling points of diesel engines is how long they last. Consider tractor-trailers — the vast majority of them are equipped with diesel engines, and it is not uncommon for them to see up to 100,000 miles of roadway in a single year. There is a reason that diesel engines are the first choice for truckers; they have a solid reputation for longevity. When maintained well, diesel engines can genuinely go the distance.
If you plan on keeping your vehicle for a very long time, engine longevity is critical. In this category, the diesel will not disappoint.
Depreciation Of Car Value
Another selling point of diesel engines is their resale value. Diesel vehicles hold their value better than gasoline vehicles, and this is mostly a result of their longevity.
Simply put, age and miles driven have less effect on the price of diesel vehicles. Use a website like Kelley Blue Book to see for yourself how well diesel vehicles hold their value compared to gasoline vehicles despite their age and mileage.
Pros And Cons Of Diesel Cars
Here is a summary of the pros and cons of modern diesel vehicles:
- Engine longevity
- Better value retention
- Better fuel economy than gasoline vehicles
- More environmentally friendly than gasoline vehicles
- Higher upfront cost
- More expensive maintenance
- The higher cost of fuel
- Inconvenient treatment is required (plugging in the block heater and the regeneration process)
Frequently Asked Questions
Now that we have discussed the pros and cons of diesel vehicles in-depth, we will answer some other questions you might have about them.
Will diesel cars be banned in the UK?
There has been talking about the future of diesel vehicles in the UK; some are under the impression that they will be banned outright. In short, diesel vehicles will not be prohibited; the UK is looking to make densely populated centers more environmentally friendly by charging people for driving vehicles that do not meet specific emissions standards. Given the fact that modern diesel vehicles are mostly ecologically friendly, you need not worry about them being banned.
Is it worth buying a diesel car in 2019?
The answer to this question largely depends on you. Diesel vehicles are by no means terrible vehicles. They do, however, come with a higher price tag in terms of the initial purchase, fuel price, and more expensive maintenance.
With that said, some people prefer diesel vehicles. The sound and feel of diesel vehicles are undoubtedly unique, and some people are willing to pay for it. If you are ready to pay the price that comes with owning a diesel vehicle, go for it!
From a purely practical perspective, however, there is little justification for purchasing a diesel vehicle, with the exception being a diesel truck for frequent towing of heavy loads that exceed the capabilities of gasoline trucks. Aside from this scenario, diesel vehicles offer no tangible benefits over other types of vehicles on the market.
We hope that this article has helped inform you about the different pros and cons of diesel vehicles and, by extension, informed your decision to purchase your next vehicle.
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