When you want to buy a new car, you may want to know the answer to: “What is the difference between a diesel and gas engine?”

Both engines share similarities. Diesel and gas engines are internal combustion engines that convert chemical energy into mechanical energy. The mechanical energy moves the pistons inside the cylinder, turning the wheels of a vehicle forward.

Also, both diesel and gas engines convert fuel into energy through a series of small combustions or explosions. However, this is where the similarities end. In terms of in-depth function and benefits, they are different. Diesel engine parts are also different from their gas counterparts.

Gas Vs. Diesel Engines

One of the most notable differences between gas and diesel engines is the thermal efficiency of the latter. Thermal efficiency refers to the amount of fuel the engine can produce, as well as the work that comes from it. Diesel engines are 20 percent more thermally efficient compared to their gas counterparts. So, if you use a diesel engine, you benefit from a 20 percent increase in fuel economy.

Its fuel efficiency makes it a common installation in a variety of vehicles and equipment – from medium-sized trucks to power generators and cruise ships. It is also common in many high-profile vehicles. Diesel’s higher fuel efficiency results in lower operating costs, which is always a big plus to car owners and business owners. Another reason behind diesel’s popularity is its reliability – the engine runs at slower revolutions per minute (RPM) compared to gas engines; therefore, it has a longer life span.

Diesel’s increased thermal efficiency also results in more torque and power. This engine’s high torque application is a plus for hauling since it can easily carry heavy loads. So, if you’re looking for a better deal on engines, diesel engines are more cost-efficient.

On the other hand, gas engines have a higher volatility point but a lower flashpoint. Fresh air compresses the fuel. Once the compression reaches a level intended by the manufacturer, the spark will ignite the air and fuel mixture, which causes the engine to run.

Diesel engines do not use a spark. Instead, it depends on a compression combusting engine, which comes with a higher compression ratio. Simply put, much pressure is placed on the air-fuel mixture, which triggers an explosion on its own.

Life Expectancy

Gasoline engines often show some wear when they hit the 120,000 to 150,000-mile mark. Eventually, you’ll notice a decrease in engine efficiency. On the other hand, diesel engines have a longer lifespan. Despite having a similar design to gasoline engines, diesel engines have removable liners. So when they reach 200,000 or 300,000 miles, you can easily replace the liner without replacing the entire engine.

As mentioned above, diesel engines have low RPM but have a high torque. Gas-powered vehicles will turn as twice as many revolutions per minute while driving down the highway. A diesel truck wears at half the rate, which explains its longer lifespan.

Finally, diesel engines are more robust compared to their gas counterparts. They have thicker castings and cylinder walls. On top of that, the oiling system has a higher volume.

Car Maintenance Considerations

In some ways, diesel-fueled engines require less maintenance since the vehicles do not use distributors or spark plugs. Thus, you don’t have to worry about ignition tune-ups. However, diesel engine maintenance requires frequent and regular oil changes, as well as the fuel filter and air changes. Diesel engine-powered vehicles also come with water-separator collection bins that you must empty regularly.

Failure to maintain your engine will result in damage. The fuel injection system can break and require costly repairs. You may also have to work with a certified diesel mechanic, which are professionals that charge high rates.

Does Diesel Have Disadvantages?

Yes. If you’re leaning towards diesel, consider the following cons that come with it as well:

  • Higher fuel costs. Diesel fuel can cost 50 cents more than unleaded fuel.
  • More expensive purchase price. Cars with a diesel engine are more expensive to purchase the vehicles with gas engines. The heavy-duty parts of diesel engines do come at a higher price.
  • Pollution.Despite advances in diesel engines, the fuel still produces harmful emissions like soot and nitrous oxide. Fortunately, the market is selling low-sulfur diesel to greatly reduce these emissions.
  • Noisier. Manydiesel cars no longer have noisy engines, but they still make more noise compared to gas engines. If noise bothers you, this could be a deal-breaker.

To determine whether diesel or gas is better for you, examine your driving habits. If you drive miles, a diesel engine is better for you. But if you don’t put a lot of miles on your car, you could save more if you stick with gasoline engines.