The global market for diesel engines is rising at unprecedented rates. This trend is expected to continue through at least 2025, which means this technology is not going to disappear at any time soon. It is a technology named for its inventor, who was a German engineer named Rudolf Diesel.
Diesel grew up in France and then decided to leave for England during the Franco-German War. When the conflict was over, he returned home to begin studying engine design concepts. During the 1880s, he made significant advancements in the steam engine concept, but the coal required to make them operate was expensive and inefficient. He wanted to create something that could help small businesses compete.
Diesel eventually discovered that he could make a small internal combustion engine that converted the heat it generated into work. One of them could even theoretically turn 75% of the heat it generated into energy. By 1904, the French started using his engines in their submarines because the fuel was heavier and at a lower risk of flammability.
This technology continues to advance, so now is the perfect time to review the advantages and disadvantages of diesel cars.
List of the Advantages of Diesel Cars
1. Diesel engines are highly efficient.
Diesel technologies use a compression-ignition system that is more efficient than what you can find on the standard gasoline model. Instead of using spark plugs to create heat for the process, diesels need more compression so that the air gets to the correct temperature. Since that means the compression level is higher, the engine operates hotter than the motors of a typical car. That means more energy is produced from the system while using less fuel to create it.
That means diesel cars typically have better gas mileage than their gasoline counterparts. You can travel further without the need to fill up again, which could potentially save you some money. You’ll receive up to 30% better fuel economy when compared to its counterpart with similar performance.
2. Diesel cars are more durable with their engine setup.
Because the diesel engine must operate at a higher temperature to be useful, engineers must build them in a way that lets them withstand this environment. That means there is a higher quality of material use and craftsmanship that goes into the final product. It is an advantage that means the technology lasts longer than gasoline-fueled products. You must keep up with all of the necessary maintenance to see this benefit, but it is an investment that is worth making for most vehicle owners.
There are several Mercedes-Benz models that have more than 900,000 miles on their original engines. Even if you are a high-mileage driver (defined as 15,000 miles or more per year), it would take 60 years to reach that top limit. Most engines can run for 300,000 miles or more without needing any major work.
3. Diesels provide you with more torque when driving.
Since a diesel engine produces more energy when compared to gasoline-fueled models, there is a higher level of torque available when driving. That means your towing capacity is going to be significantly higher for whatever car you decide to own. If your goal is to own a travel trailer or you need to regularly haul heavy loads, then this technology will give you the extra power needed to get the job done.
This advantage means that you can drive a smaller diesel car while still getting a performance that is close to that of a gasoline-powered passenger vehicle. Many of them can achieve a 0-60 acceleration profile that takes 7 seconds or less while still getting up to 40 miles per gallon.
4. A diesel car has a better resale value.
Assuming that you kept up with the standard maintenance schedule with your diesel car, you’ll discover that there is a better resale value with these vehicles. Even if the body of the car isn’t in tip-top shape, the quality and longevity of the engine will make your diesel continue to be a tempting offer. Their durability, performance, and overall handling make them a useful option long after their gas counterparts wear out.
5. Diesel fuel quality has improved dramatically over the past 20 years.
New diesel cars in the United States must meet the current EPA guidelines regarding fuel standards and emissions. Most adults can remember in the 1980s and 1990s when these vehicles were dirty, smelly, and heavy pollutants of the environment. Now, this fuel is cleaner than it has ever been before. The invention of ultra-low sulfur diesel helped the industry to start transforming in 2006, and this fuel is now required to meet on-road and off-road fuel standards. The current rate of sulfur content is limited to less than 15 parts-per-million, but the previous standard was up to 5,000 ppm.
When the improved fuel works with an advanced exhaust emission control system, particulates go down by 90% and nitrogen compound emissions reduce by up to 50%. You do need to purchase a newer diesel engine to take advantage of this benefit.
6. The price difference for some diesel cars is minimal.
Diesel cars do cost more than ones that operate on standard gasoline. Smart shopping can help you to reduce the differences dramatically. If you were to purchase the turbo-diesel Volkswagen Jetta, then you would spend about $2,500 more to take advantage of this technology. Driving that car on the highway consistently would help you to reduce your overall ownership expenses over time. You could also go after Volkswagen’s Golf TDI to achieve a similar result.
7. You can burn more than one type of fuel in diesel cars.
If you purchase an engine that operates on unleaded gasoline, then that is your only fuel choice. You can use ethanol blends to a certain extent, but that will decrease the gas mileage you receive. When you choose a diesel car to drive, then you have the option to burn more than one type of fuel. If you are of a frugal mindset, then waste vegetable oil (WVO) is an option. Most restaurants will give you the grease they create for free. You’d need an engine modification to prevent the oil from congealing, but it works.
You also have the option to create biodiesel by yourself at home. You can’t refine gasoline if it comes to that need, which means you’ll have more flexibility with this vehicle option.
8. Some diesel engines can operate quietly.
The 2018 Chevy Equinox uses a 1.6L turbo-diesel engine that earns the nickname of “whisper.” It provides a foundation of support that works to mute its noise and the amount of vibration produced when driving. General Motors says that the engine is 65% quieter than what you would experience in Jaguar’s F-Pace diesel. This vehicle also provides a 577-mile cruising range, which means you can experience a longer time behind the wheel without experience the same levels of physical exhaustion since there is less sound and vibration happening.
List of the Disadvantages of Diesel Cars
1. Diesel cars usually cost more than a standard vehicle.
You’ll find that a diesel car will cost several thousand dollars more than a similarly equipped one with a standard gasoline engine. The quality of the work that goes into the engine is what usually is the difference in the MSRP. You must start with the quality of the materials first, and then the quality of the fuel used in the car will contribute to the longevity of the investment. You can end up spending a lot of money on something that turns out terribly for you if using the wrong quality of fuel for the engine.
The Jeep Grand Cherokee EcoDiesel is one example of this disadvantage. It may have an appealing engine for long-distance driving, but it will also add another $4,500 to the base price of the vehicle. Most people would be unable to recoup that additional expense in the United States with their driving habits.
2. The cost of diesel fuel is pricey in most geographic regions.
You won’t need to fill up your tank as often when choosing to drive a diesel car, but you will be paying more for the fuel needed to fill it up. If you are a daily driver in stop-and-go traffic, then you’ll need to weigh the value of the improved fuel efficiency with the cost of your commute. One of the reasons why it is more expensive in the United States is because the tax rate is $0.06 per gallon higher for diesel compared to unleaded gasoline. The demand for diesel internationally is also high, which pushes the cost up as well.
All prices are variable, but you can expect to see the cost of diesel be at least $0.30 higher per gallon at most fuel stations. There are times when it may be more than $1 per gallon (or liter) more to purchase.
3. It will cost more to repair a diesel engine.
Diesel engines might offer the benefit of higher durability, but they also create issues with repair costs if they break down for some reason. Comparable repairs with a gasoline engine are always higher when you decide to roll with a diesel car. That’s why it is imperative for you to keep up with the regularly scheduled maintenance of your vehicle. If you’re thinking about purchasing a used vehicle, then you’ll want a trusted mechanic familiar with this technology to inspect the car to ensure that it is in a good running condition.
4. You won’t receive the same high-speed performance with a diesel car.
Diesel fuel is more efficient because of the way that it converts heat into energy, just like the original concepts from the first prototypes did in the past. That means the heat doesn’t go out of the tailpipe and become lost forever. Since engines are often measured in horsepower, it can be helpful to compare diesels and gasoline-powered designs in the same way.
If you own a diesel car, then you are going to have a workhorse. It might be slower, but you’ll have a stronger engine that can endure a variety of challenging conditions. Owning a gasoline-powered car means that you’ll have something more like a racehorse to drive. It is fiery, fast, but remarkably high-strung and needed more attention to stay healthy.
5. There may be water separators that you need to manage with the engine.
Diesel cars might not need new distributors or spark plugs so that you can save on ignition tune-up expenses, but they still require regular maintenance. That means you will need to change the fuel, oil, and air filters on the appropriate schedule without delay. The cleaner fuels that you can run today with your diesel engine don’t require bleeding off the excess water in the system, but most cars still have separators that require you to manually empty them periodically.
6. You may not have as much access to the fuel that you need with diesel.
If you live in Iceland, Ireland, and other European countries, over 70% of the cars on the road might have diesel engines powering them. When you come to the United States, that figure can drop to less than 10% in some communities. That means you will not have as much access to the fuel you need for your vehicle. About 50% of all gas stations have one pump for diesel fuel, which means traveling can be a challenge at times. You’re forced to stick to the routes used by truckers to ensure that there is enough fuel availability present.
7. The new diesel fuel doesn’t have the same lubricating qualities.
Using Ultra-Low Sulfur Diesel might reduce the number of particulates and emissions that a car produces while driving, but it also doesn’t keep the lubricating qualities as it did with previous engines. That means some of them can begin to wear out much faster than they did in the past. Some experts recommend that you use additives with your fuel if the engine was built before 1997 to make up for what happens with this disadvantage.
You’ll also have the hassle of managing anti-pollution equipment to maintain this profile. Your urea tanks must receive regular filling, which can be up to $40 per service. Since this is a rather new technology, no one really knows what the longevity of this equipment will be.
8. It can be challenging to start a diesel engine in cold weather.
If you live in a colder climate, then driving a diesel car can be challenging if you must park it outside. When temperatures drop below freezing, then it becomes more difficult to start the engine. This disadvantage grows as the cold intensifies, with temps below zero extremely problematic. You must have a higher temperature available to ignite the fuel, so it becomes necessary to use a block heater to keep the compartment warm when you’re not driving. If you travel frequently and don’t have access to a power source for this need, then it might be a challenge to get going in the morning.
9. Diesel engines are louder than their gasoline counterparts.
If you want to operate a vehicle that is quiet, then a diesel car is not the right choice to make. This technology will always be louder than when you drive something powered by unleaded fuel. Automakers can reduce this disadvantage a little by increasing the number of sound-deadening materials that surround the engine.
A standard diesel engine produces 100 decibels of noise. When you include the additional sounds of accessories and equipment, the driving experience can become deafening. You can avoid all of those issues by switching to a gasoline-powered engine, which produces 75 decibels when driving at 65 miles per hour. Anything above 85 decibels could create the potential for hearing loss.
When you look at the advantages and disadvantages of diesel cars, you’re balancing reliability with performance. If you want something sporty, fiery, and ready to burn rubber, then a gasoline-powered engine is the better choice to make. Diesels will always be workhorses before anything else.
There is a cost consideration to look at since the MSRP of a car with a diesel engine is several thousand dollars more. If you can afford the expense, then the cost savings of better fuel efficiency and less formal maintenance can get you out of the red eventually. Failing to keep up with your upkeep can result in much higher expenses, which is another consideration to look at.
Diesel engines excel at traveling over highway miles. If you are always in stop-and-go traffic in the city, then your mileage difference might not justify the investment. When you travel long distances at highway speeds, then you could save a lot on your fuel costs over time.
Keith Miller has over 25 years experience as a CEO and serial entrepreneur. As an entreprenuer, he has founded several multi-million dollar companies. As a writer, Keith's work has been mentioned in CIO Magazine, Workable, BizTech, and The Charlotte Observer. If you have any questions about the content of this blog post, then please send our content editing team a message here.