September 22

What You Should Know about Diesel vs Gas Engines


Last Updated on September 23, 2022

Why do some auto manufacturers offer vehicles with diesel engines over gasoline? And why do some people want gasoline engines rather than diesel? Should you drive a car with a diesel engine or should you opt for gasoline instead? If that’s what you’re wondering right now, we can help. Here’s what you should know about diesel vs gasoline engines.

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Although both are types of fuel and any vehicle can be equipped with either a diesel or gasoline engine, the two don’t have the same characteristics. Since they operate a little differently from one another, this means different performance outcomes.

Both diesel and gasoline are hydrocarbon compounds derived from crude petroleum oil. However, diesel has more hydrocarbons with longer, heavier molecular chains and more carbon atoms. Gasoline has more hydrocarbons with shorter, lighter molecular chains and small molecules. 

Diesel fuel is thicker, heavier, and oilier than gasoline. It also has greater energy density, which leads to greater heat and energy production (about five percent more) compared to gasoline. This type of fuel smells of oil and kerosene. 

Gasoline more easily ignites and changes from liquid to vapor than diesel. That’s because it’s lighter. Gas also doesn’t smell as strong, but can cause a retching sensation.

Never put gasoline in a diesel engine or vice versa because this will wreck the engine. However, diesel fuel becomes sludgy in cold temperatures, so some people put a little gasoline in their tanks to loosen the die fuel. This appears to have no damaging effects on the engine. 

diesel versus gasoline infographic

Superior pulling power 

Between the two fuels, the primary differences in performance characteristics are torque (towing) and horsepower (acceleration). 

Diesel engines are able to create more mechanical power. That’s why the construction industry uses them – the machines can lift, push, and haul more. 

Gasoline engines are high revving and high rpm, which translates into greater acceleration. That’s why all race cars are equipped with gasoline engines. Police cars have gasoline engines too. Any vehicle on which you want acceleration and high speed should have a gasoline engine. 

Compare the towing capacities on these diesel and gasoline-powered trucks

diesel versus gasoline powered trucks infographic
  • Ford F150 18,200 pounds (6.7 L Turbo Diesel)
  • Ford F150 15,000 pounds (6.2 L V8)

(Both F150s are Crew Cab Standard Bed)

  • Ram 1500 12,560 pounds (3.0L EcoDiesel V6)
  • Ram 1500 6,600 pounds (3.6 L V6 24V VVT eTorque)

(Both Ram 1500s are Crew Cab Standard Bed)

  • Chevrolet Siverado 1500 13,000 pounds (Turbo-Diesel 3.0L I6 LM2)
  • Chevrolet Siverado 1500 11,000 pounds (5.3L V8 L84)

(Both Silverado 1500s are Double Cab Standard Bed with NHT)

You can see the trucks with diesel engines have moderate to significant advantages in the towing category. 

Superior fuel efficiency

Diesel engines are more fuel efficient than gasoline engines (by about 20-30 percent). Since they have a greater power density, they provide more miles per gallon. 

If diesel fuel didn’t cost much more than gasoline, then people would save so much money by switching to vehicles with diesel engines. Gasoline is sitting just above $4, while diesel is sitting just above $5. That 20 percent increase in fuel price wipes out most or all of the 20-30 percent fuel efficiency gain achieved from using diesel. 

Superior longevity 

Diesel engines are known to last longer. They have much larger crankshafts, camshafts, and cylinders, as well as larger bearing sizes. This means that there is more room within the engine for oil to move freely. The larger oil and coolant capacity of a diesel engine allows for better lubrication and less wear. In fact, the average gasoline engine will use around one gallon of oil, whereas a large diesel engine can use 15 gallons.

Less repairs, greater costs 

Although diesel uses more oil, you will get more miles per gallon on a diesel engine than on a gasoline engine. Vehicles with diesel engines can achieve 7,500 miles per gallon, whereas gas-powered vehicles require an oil change every 3,500 to 5,000 miles. However, garages tend to charge more for oil changes on diesel engines (sometimes double the cost). 

Diesel engines use gears, which are more difficult to damage than the timing belts, chains, and pumps found on gasoline engines. And, diesel engines use compression ignition, which causes spontaneous combustion. This is more advantageous for a long-lasting engine.

Spark plugs and distributors, which are found on vehicles with gasoline engines but not on diesel ones, are a major contributor to earlier engine repair.

Since diesel fuel is a heavier oil, the components on a diesel engine must be heavier-duty to withstand it, so components tend to last longer before needing to be replaced. However, components that are more durable tend to be more costly. You will be visiting the mechanic less often, but you can expect to pay more each time you go. Due to this offset, whether you save money on vehicle repair compared to a gasoline engine is really up in the air. Many other factors, such as how the vehicle is driven and maintained, will have a bigger impact on vehicle maintenance costs.  

Also important to know, since diesel engines are less common, parts could be less available. There may even be less technicians trained for working on them, not just that garages tend to charge more for these services. 

Pay more up front

Vehicles with diesel engines cost more up front than their gasoline counterparts. 

Not every vehicle has diesel and gasoline engine options, nor does every trim. On trucks, for example, diesel isn’t available on vehicles with basic trims and cable sizes. You have to upgrade to a crew cab. And, even when comparing a crew cab gas-powered truck to a crew cab diesel-powered truck, you end up paying a little more. 

Also, owners of vehicles with diesel engines tend to pay 10-15 percent more to insure the vehicle

Final thoughts

There are numerous considerations to make when choosing between diesel and gas-powered engines, including convenience features and what gas stations near you offer. Not all of them provide diesel fuel. You could be fueling your vehicle next to big rigs. There is also the opportunity to decrease your carbon footprint by using biodiesel in your diesel engine instead.

Or maybe gasoline is your preference, especially if you’re looking to get behind a police vehicle or some other fast car. Refuels and repairs won’t cost nearly as much as relying on diesel fuel. 
Whatever you pick, every distinction between the two types is a tradeoff, so choose wisely. And while you’re at it, what better time than now to select a new vehicle for yourself altogether? Municibid offers wide selection from trucks and cars, all of which you can start browsing today.


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