Diesel vs. Gas: What are the Differences?

One thing you would consider when getting a vehicle is the engine it has: diesel vs gas. Interestingly, there appear to be more diesel engines in the American auto market because of diesel engines’ benefits. Given that diesel and gas are both fuels, it is only natural that the question “What is the difference between diesel and gas?”.

The answer to this question will affect your driving experience because it will help you decide on the right vehicle engine to have. As much as diesel engines have benefits, they also have flaws that might be the gasoline engines’ strengths.

This article will focus on the differences between the fuels, the pros and cons of their engines, and the pricing of both fuels. We will also compare the chemical composition and efficiency of both fuels. At the end of the article, you should be able to answer the question, “What is the difference between gas and diesel?”

What Is The Difference Between Diesel And Gas?

Gasoline and Diesel fuel are hydrocarbon compounds derived from crude petroleum oil. So, one of the most apparent differences in the boiling point because gasoline boils off before the diesel during the crude oil distillation process.

 Gasoline contains a larger concentration of hydrocarbons with shorter, lighter molecular chains and small molecules. Because of its lightness, gasoline can easily change from liquid to vapor, so it ignites easier than diesel.

In contrast, Diesel has more hydrocarbons with longer, heavier molecular chains and more carbon atoms. Because of the weight of its chains, diesel does not evaporate as quickly as gasoline.

Diesel is thicker, heavier, and oiler than gasoline and has more energy density. Hence, it produces more heat and energy than gasoline. Gasoline and diesel contain different amounts of energy after being burned in a vehicle’s engine. It gives more energy (about 5% more) per liter. Diesel yields about 35.8 MJ/L as against the 34.2MJ that gasoline produces per liter.

Thanks to technological advancements, there is an environment-friendly option for diesel known as biodiesel. This option is made from non-petroleum sources and is fast becoming an eco-sustainable alternative for fueling modern vehicles.

Diesel and gasoline are both used as fuel in internal combustion engines. However, the combustion process is a major difference between the gas engine and diesel engines. Diesel ignites itself using the high compression ratio present in diesel engines. This ignition can’t occur in a cold engine, so glow plugs must start diesel engines because the diesel solidifies at that low temperature.

 This explains why diesel engines require batteries bigger than their gasoline counterparts. The larger batteries are necessary to neutralize the high compression ratio and power the glow plugs.

You might find much soot formed from the high-pressure combustion of the diesel. You may also need to get your engine oil changed because some of the soot ends up on the internal engine components.

Gasoline runs fine during the cold weather – thanks to the sparks generated by the spark plugs in the engine.

Some mechanics recommend you add 10% petrol to the diesel in the tank during the winter when the diesel gets sludgy, but what happens if you put diesel in a gas car?

If you turned the engine on, it would stop running because the diesel would damage it. If you haven’t turned the car on, your best bet would be to stop adding the diesel and have experts take care of the situation ASAP.

Suppose you find yourself with gasoline in your diesel engine. You would have to avoid starting the engine. If you do, the engine’s injectors and seals will get damaged, causing severe damage to internal engine components.

Diesel Vs. Gas Trucks Pros and Cons

Many potential truck owners put a lot into consideration when deciding on the truck to buy. One of the most crucial factors to consider is the truck’s engine. Most folks looking to get new trucks are ignorant of the difference between gas and diesel trucks. That is why we will compare the pros and cons of both types of trucks.

Pros of a Diesel Truck

  • High torque
  • Excellent heavy-duty capability
  • Great mileage
  • Improved longevity
  • Eco-friendly

Cons of Diesel Trucks

  • Pricey
  • Fewer diesel fuel stations

 Pros of a Gas Truck

  • Easy access to gasoline fuel stations
  • Great payload
  • Cheaper Maintenance
  • Easy to get professional mechanics

Cons of Gas Trucks

  • Poor Mileage
  • Poor Resale Value
  • Low Torque

Diesel Vs. Gas Price

Diesel has always cost more than gasoline because of environmental embargoes and taxation. At a point, diesel costs as much as 76 cents on the gallon more than gasoline. There has been a federal excise duty of 24.4 cents on the gallon for diesel against 18.4 cents for gasoline.

Although there is a difference in gas and diesel prices, diesel has better mileage than gasoline because of its fuel efficiency.

Diesel Vs. Gasoline Efficiency

Because of its chemical composition, diesel is more efficient than gasoline. Diesel requires high air compression to self-ignite, and diesel engines convert thermal energy to mechanical energy from diesel combustion. Therefore, you find the diesel engine in more vehicles (including ocean liners) than gas engines. It all boils down to the thermodynamic efficiency of the fuels. Diesel engines produce more mechanical power than gas engines per liter.

Diesel Vs. Gas Color

Gasoline is clear with a tint of amber sometimes, whereas Diesel could be yellow or clear. Get a comprehensive answer on diesel vs gas color here.

Diesel Vs. Gas Engine Life Expectancy

The diesel vs gasoline comparison has gone on for a while because of the life expectancy of their engines. Diesel engines require high compression to burn fuel. This leads to thorough combustion that minimizes the corrosion that damages the vehicle’s components like the crankshafts, engine block, valves, exhaust, and piston.

The reduction in corrosion enhances the longevity of these components and allows most diesel engines to cover at least a reasonable mile before repair or maintenance is needed.

Diesel engines also come with removable liners in their cylinders, which you can replace after a few hundred thousand miles to increase the engine’s longevity. The combustion process in gas engines is more corrosive, and so after a few hundred thousand miles, the process takes a toll on the engine’s components, leading to wear and tear.

In addition, gasoline engines have a high RPM, so there are more revolutions in the gas engine, leading to increased wear and tear of the engine.

Gas engines don’t come with a replaceable cylinder liner that helps manage the wear and tear of their combustion and operation pattern.

The build of the engines also plays a role in their longevity. Diesel engines have to handle high compression, so they are sturdier than gasoline engines.

Gasoline Vs. Diesel Chemical Composition

Diesel and gasoline have hydrocarbons, although the hydrogen-to-carbon ratio differs. In addition, diesel has naphthenes, paraffin, and aromatics. Gasoline comprises alkanes, alkenes, and aromatics. There is also a difference in their structure, with diesel having straight chains, unlike gasoline with branched chains and cyclic hydrocarbons.

diesel vs gas price


What Is Better Diesel Or Gas?

Both fuels have pros and cons that balance each other out. While diesel might be more fuel-efficient and eco-friendly, gasoline is cheaper and more accessible. Gasoline is better suited to acceleration and horsepower, while diesel produces more mechanical energy and torque.                                       

What Is Worse, Diesel Or Gasoline?

It all depends on the context. Sometimes, you need the torque and power of a diesel engine, while you might need the acceleration and speed of a gasoline engine. However, there is the opinion that diesel engines might facilitate global warming a lot more than gasoline engines.

Is Gasoline A Diesel Fuel?

No, it is not. Rather, gasoline is a fuel like diesel, and both are by-products of crude oil distillation.

How Can You Tell If Gasoline Is Diesel?

Gasoline is not diesel, although both come from the same source of crude oil. It is also easy to spot the difference in both fuels. Diesel is thicker and a lot oilier than gasoline. It also has a boiling point higher than gasoline and does not evaporate.

Does Diesel Smell Different From Gas?

Both fuel types smell differently. Diesel smells like oil and kerosene, with a pungent aspect to it. Gasoline’s less aromatic smell gives a retching sensation. If you are looking for how to tell the difference between gas and diesel in a can, you can tell the difference by smelling them.

Final Words

We live in an automotive world that keeps evolving by the day. Car manufacturers are trying to one-up each other with their products and optimize their engines. Two types of fuel power are these engines, and if you are looking to get a vehicle, you should have a fitting response to the question, “what is the difference between diesel and gas?”

The article described the characteristics of both fuels. It also has focused on the pros and cons of their use in their respective engines. You now know what each fuel offers and the engine that works for you. Better still, will no longer be confused by questions like “Is gasoline diesel”?

Osuagwu Solomon

Osuagwu Solomon is a certified mechanic with over a decade of experience in the mechanic garage, and he has over five years of experience in the writing industry. He started writing automotive articles to share his garage experience with car enthusiasts and armature mechanics. If he is not in the garage fixing challenging mechanical problems, he is writing automotive repair guides, buyer’s guides, and car and tools comparisons.

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