Which Type of Gas Does Your Car Need?


You've probably heard that most cars run with regular gas. But when you pull up to the pump at your local gas station you see several different grades of gas and even different types of fuel. You might wonder why these different types and grades exist.

Using the right fuel type and grade is important because using the wrong fuel could potentially harm your car's engine.

Different Fuel Types

Most cars run on gasoline, a refined petroleum distillate. Gasoline makes up the majority of options at your local gas station. However, there are other types of fuel as well.

Diesel is a different type of fuel obtained from crude oil. Some gas stations offer biodiesel, which comes from vegetable oil. Diesel is more expensive than gasoline, but it allows you to drive longer distances. It only works on vehicles designed to run on diesel fuel. If you use gasoline in a diesel engine damage will likely occur as gasoline does not ignite properly and burns too quickly resulting in very low power output of the diesel engine.

Today, many vehicles are built to run on alternative fuels. E85 is the most popular and is a blend of 15% gasoline and 85% ethanol. It is less expensive than gasoline but leads to lower miles per gallon. There should be a decal or label on your car identifying that it is E85 compatible (also known as flex fuel).

Other alternative fuels include liquefied petroleum gas, compressed natural gas, and liquid nitrogen. However, most vehicles are not built to accept these fuels.

Electric cars are gaining popularity. They run on electricity rather than gas. Before these cars can drive, the operator needs to be sure the battery is sufficiently charged. Some hybrid models use both a gasoline engine and an electric engine to power the vehicle. The combination is set up to allow the car to run as efficiently as possible.

How Gas Grades Work

Now that you understand the different fuel sources, let's explore the different fuel grades. But first you need to understand why these different grades exist.

As you look at the different gas grades at the gas station, you'll notice that each grade has a number. This number is the octane rating, which measures how resistant the gasoline is to pre-ignition. When your gas ignites prematurely, you'll hear a rattling or knocking sound. This usually means you have used a lower octane rated gasoline than is recommended for your car. The higher the octane rating, the more resistant the gas is to pre-ignition. Most cars are designed to combat the effects of pre-ignition.

Differences Between Gas Grades

Most cars' engines are built to withstand pre-ignition. Thus, regular gas is a perfectly acceptable choice. Some luxury and high performance cars are equipped with higher compression engines, which are more likely to experience pre-ignition. These cars likely require a premium grade of gas. It is important that you read your owners' manual to confirm the octane rating required for your car. You should follow the factory recommendation, especially during the warranty period.

Choosing the wrong fuel type or grade can be a waste of money and could damage your car's engine. Manufacturers have spent significant testing time to determine the best fuel rating for your vehicle. The best bet for any car is to follow the manufacturer's recommendation when choosing the correct fuel for your car.

Read through the rest of our blogs to learn more about car maintenance, or, if your old car is on its way out, consider donating it to Newgate School.