In the US, there are approximately 116,000 gas stations. Once you pull in for a fill-up, most customers encounter a few choices. Regular, plus (or mid-grade), and premium are common for unleaded gas. In most cases, you’ll also find diesel available.
It isn’t uncommon to wonder, “What’s the best gas for my car?” when you look at these options. Will premium give me better performance? Could regular damage my engine? What happens if I use diesel?
While it might be confusing on the surface, figuring out which one is right for you is fairly simple. However, it is helpful to understand what the different choices mean.
Different Types of Gas
At a gas station, unleaded fuel is usually available with three octane levels. 87, 89, and 91 or 93 are the most common offerings at most gas stations.
The octane rating isn’t an indication of power. Instead, it plays a role in preignition.
To operate, your car’s engine starts compressing fuel and air as it ignites them with a spark. Preignition occurs when the fuel-air mixture ignites too soon, something that can lead to a knocking sound.
Octane levels denote a fuel’s resistance to preignition. Higher ratings mean the gas isn’t as likely to detonate, and certain engines can use this feature to achieve more power.
In a high-performance engine, the fuel-air mixture is compressed to a smaller size. This creates additional heat, something that could lead to preignition with low-octane gas. High-octane fuel prevents preignition in these engines, allowing it to function at its best.
Diesel engines ignite differently than traditional unleaded gas engines. Diesel engines don’t use sparks. Instead, the compression creates enough heat to cause combustion. This means fuel a diesel engine needs features a different composition.
What Is The Best Gas For My Car?
Generally, the easiest way to figure out which type of fuel is best for your car is to check your owner’s manual. You may also find this information near your gas cap, though this isn’t always the case.
Your vehicle is designed to run on a gas that features a certain minimum octane. If your car can use 87-octane fuel, then springing for a higher grade isn’t necessary. You won’t get a performance or mileage boost by investing in more expensive gas in most cases, so don’t waste the money and just buy regular.
However, if your car needs a plus or premium octane, usually between 89 and 93, then that’s what you need to buy. In older vehicles, buying a lower octane can actually cause damage to the engine, making it a necessity.
While newer cars have sensors that can retune the engine, helping to prevent damage from a lower octane, that doesn’t mean it is good for your engine. Your fuel economy will usually suffer, and you may see a reduction in power. Additionally, there’s no guarantee that your engine won’t experience damage, even if it has the latest technology.
If your vehicle doesn’t ask for diesel, then don’t use it. Putting diesel into a regular gas tank can cause your car to stop working. Diesel fuel is thicker than regular gas, so it can gunk up your injectors, lines, and filters.
While the damage isn’t always permanent, it can be, so it’s best to find a mechanic who can help you remove the fuel quickly. Allowing the diesel to sit in your tank and fuel system can lead to additional damage, so it needs to be siphoned out by a professional.
Don’t drive your car to the mechanic. Instead, you’ll need to pull over somewhere safe and get a tow truck to take your vehicle to a shop. This lessens the likelihood of damage, making it a crucial step.
Luckily, many diesel nozzles won’t fit in a regular gasoline fuel tank, so you aren’t likely to make this mistake at the pump.
Similarly, if your car needs diesel, then that’s what you need to use. Putting regular gas into a diesel vehicle can also harm the engine, especially with “clean diesel” engines. Again, your best bet is to call a tow truck and head to a mechanic.
Does Brand Matter?
Certain fuel stations, like ARCO, Costco, and Walmart, are known for lower prices. This leaves many wondering if the cheaper price is a reflection of the quality of the fuel.
In reality, the federal government has strict guidelines regarding gasoline, especially octane ratings. This means an 87-octane fuel at a cheap gas station has the same octane level as an 87-octane fuel at any other.
In most cases, the primary difference is the presence or lack of additives. For example, some stations have detergents that their brand uses, while others may not. If you choose a station that doesn’t use additives, then you might want to purchase some fuel injection cleaner. Then, you can add a little to every tank and get a similar advantage to the additives in many cases.
Ultimately, if you choose a cheaper brand of gasoline, you aren’t necessarily endangering your vehicle. You may just have to handle the addition of cleaners yourself, ensuring everything operates properly over the long-term.
But, if you don’t want to keep track of that, then choosing a gas station that has fuel with additives may be more convenient. The price difference may only be a few cents a gallon, which may be worth it to avoid the hassle.
Is there a particular fuel that you think is best for your car? Tell us your thoughts in the comments below.
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Looking for more great articles about cars? Here are a few to get you started:
- Is It Better to Keep Your Gas Tank Full or Empty?
- Is ARCO Gas Bad for Your Car or Is It the Same as 76, Exxon, Shell and Chevron?
- Summer Car Maintenance Tips to Beat the Heat
- Costco Gas Is Cheaper, Here is When You Get It
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Tamila McDonald is a U.S. Army veteran with 20 years of service, including five years as a military financial advisor. After retiring from the Army, she spent eight years as an AFCPE-certified personal financial advisor for wounded warriors and their families. Now she writes about personal finance and benefits programs for numerous financial websites.
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