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Best Fuel Stabilizers: Top Options to Clean Fuel

Keep your fuel fresh and clean your vehicle’s fuel system with fuel stabilizer.

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BY Heather Fishel / LAST UPDATED ON July 23, 2021

OUR QUICKLIST

Has your car been sitting with gas in the tank, waiting in your driveway or garage for months without being driven? If you didn’t add a fuel stabilizer into your gas tank before your car began to sit, you could discover an unpleasant surprise when you do finally get behind the wheel again. Over time, both gasoline and diesel fuel can break down and deteriorate. And as these fuels age, they can leave behind gummy, gunked-up deposited throughout your engine. But if you use a fuel stabilizer, you can keep your fuel fresh, properly balanced, and perfectly stable with no evaporation — and no left-behind deposits in your engine.

 

Fuel stabilizers can extend the life of your car’s fuel for as long as two years. They can even be used for gas you’re storing in fuel cans or for your lawnmower, snowblower, chainsaw, and other gas-powered items. If you’re hoping to maintain great performance and long-term functionality, a fuel stabilizer is a must-have. Check out our picks for the best fuel stabilizers, plus our tips for choosing a great stabilizer, right here.

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Our reviews are driven by a combination of hands-on testing, expert input, “wisdom of the crowd” assessments from actual buyers, and our own expertise. We always aim to offer genuine, accurate guides to help you find the best picks.

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Benefits of Fuel Stabilizers

  • Save fuel. If you're keeping a vehicle or any gas-powered equipment in storage, chances are there will still be some gas left in its motor. Instead of draining it or letting it sit and go bad, fuel stabilizer will keep your fuel fresh for the duration of storage. 
  • Eliminate cold starts. The first time you start an engine after it has been sitting can sometimes be a pain. This is because sitting idle isn’t good for your motor, but using fuel stabilizer will help your engine and make that first start quick and easy.
  • Clean your fuel system. No matter what type of fuel you use, there are going to be impurities that will build up in your fuel system. Using fuel stabilizer will clean out the impurities and protect your vehicle from corrosive condensation build-up.
  • Performance. The buildup in your engine causes your motor to work harder to run. This hinders your engine's abilities and takes away from its performance and fuel economy. Cleaning your fuel system will ensure your engine runs better, boosting performance and fuel economy.

Types of Fuel Stabilizer

Storage

While every fuel stabilizer has the same primary goal in mind, each one is formulated differently for specific areas of protection. Fuel stabilizer is used to keep fuel fresh while sitting in storage, and storage-based formulas have longevity in mind. These formulas are specially designed to keep fuel fresh for as long as possible, with many claiming up to two years of protection.

Performance

A performance-based fuel stabilizer is still great for keeping fuel fresh. However, they tend to keep fuel clean for less than 24 months. Instead, they are formulated to get the best performance and efficiency out of your vehicle by breaking down build-up from fuel impurities. 

Top Brands

Sta-Bil

Sta-Bil is a popular brand owned by Gold Eagle Co. The company, founded in 1932, has been an industry pioneer in producing aftermarket fluids and additives. This Chicago-based business markets over 100 branded products, including Sta-Bil fuel stabilizers specialized for performance, marine, and diesel uses.

Marvel Mystery

This Chicago-based company got its start in 1923. The founder, Burt Pierce, made a name for his company by producing parts for the vehicles used during World War I. Later, issues with carbureted vehicles like clogged fuel systems grew, and products like Marvel Mystery Oil MM12R were born.

Starbrite

This company is behind the top-rated Star Tron Enzyme Fuel Treatment. Starbrite got its start in 1973 as an auto polish company. In the 80s, the company expanded its line to include the boat care and appearance market. Today, it makes treatments and additives for a vehicle, aircraft, home care, aviation, lawn mowers, motorsports, and motorcycle markets.

Sea Foam

In the 1930s, Fred Fandrei wanted to keep his boat from having fuel-related issues. As a petroleum salesman, he managed to create a formula that kept fuel from going bad and helped his motor run smoothly. Since becoming an official product in 1942, Sea Foam RV SF-16 Liquid has become a favorite choice among mechanics and car enthusiasts.

Fuel Stabilizer Pricing

  • $15 to $20: Most fuel stabilizers are priced between $15 and $20, making it an affordable investment whether you’re buying a basic or premium product. You’ll find all different kinds of fuel stabilizers from a wide array of brands within this price range, all in 8-ounce or 16-ounce containers.
  • $20 and up: If you’re looking for a whole gallon — or more — of fuel stabilizer, expect to spend $20 or more. You can buy your fuel stabilizer in bulk if you pay more, and you’ll be able to shop the same brands and types of products.

Key Features

Ease of Use

The idea behind using fuel stabilizer is to give you peace of mind when your gas-powered vehicle is sitting untouched for prolonged periods of time. So one of the most important features of a fuel additive is how easy it is to use. This applies to the container design and how easy it is to measure out the correct amounts for peak protection.

Compatibility

Using a fuel stabilizer isn't going to help you much if the additive you use does not work with your type of fuel. There are differently formulated products for gasoline, diesel, and ethanol blends. Each product will tell you exactly what kind of fuel they should be used with and how much needs to be used per gallon.

Other Considerations

  • Winter Formula. Gas motors are more vulnerable to carbon deposits in colder climates. Storing fuel during the winter has its own setbacks, so you need the best fuel stabilizer for winter storage. Winter-formulated additives will further protect your vehicles and snow blowers from corrosion and build up.
  • Length of Time. If you need to keep your fuel fresh for a certain amount of time, then you'd better know how long certain additives last. The best fuel stabilizers are rated for 24 months of protection, so if you're storing fuel for nearly two years, you'll need one of the longest-lasting stabilizers. If you aren't storing your product for too long, then other factors can take priority over longevity.
  • EPA Registration. Not all fuel stabilizers are registered with the EPA. EPA approval or registration is vital to make sure you’re choosing a product that’s good for both your car’s engine and the roads you’re driving on. This specific designation will tell you that a particular stabilizer is perfectly safe and suitable for you to use.
  • Alcohol-Free Formula. One of the key ways fuel degrades over time is through too much water absorption. And any fuel stabilizer that contains alcohol in its blend of ingredients will make this a much bigger problem for your vehicle. Any alcohol present will make water absorption happen, and it’ll fail to protect your fuel correctly.

Best Fuel Stabilizers Reviews & Recommendations 2021

Best Overall
Star Tron Enzyme Fuel Treatment

For our top pick, we chose Star Tron's Enzyme Fuel Treatment. This additive has unique enzyme technology that is specially designed to work great for both your daily driver or a vehicle you keep stored for months at a time. It's used to stop ethanol fuel problems and prevent phase separation.


This fuel stabilizer additive eliminates and prevents ethanol fuel problems by breaking down excess water and sludge. The smaller particles are safely burned up when running your engine. The cleaner fuel system will allow your vehicle to operate more efficiently and give you better performance. The added efficiency can also lead to a considerable improvement in your overall gas mileage. This additive also guarantees two years of protection for your fuel system.


While this is the best fuel stabilizer for ethanol fuels, it isn't perfect for every job. Specifically, it's not applicable for diesel fuel (Star Tron offers a separate additive for diesel). The bottle design is also awkward, which can make it difficult to pour into your vehicle. 

Best Value
STA-BIL 22214 Fuel Stabilizer

Sta-Bil not only offers one of the best fuel stabilizers, but this product is also the most affordable option. This fuel additive is a great choice for protecting your vehicle from typical build up or keeping it in good, running condition while it stays idle for prolonged periods. 


Its stabilizer formula really stands out as one of the best options for winter storage. It can be used in any gas-powered vehicle you plan on storing for more than a month. It will keep the car's fuel fresh for up to 24 months, which eliminates the need to drain your fuel tank. The fuel additive guarantees a quick and easy start even after storage. It removes water from the fuel system to help prevent any corrosion. 


While it is one of the best gasoline additives for storage, Sta-Bil fuel stabilizer isn't ideal for every situation. If you're looking for an additive to improve the gas mileage in your daily driver, there are better options out there. Also, this formula works great with gas-powered cars and equipment, but cannot be used with diesel engines.

Honorable Mention
Sea Foam RV SF-16 Liquid

Our honorable mention is often marketed as the best marine fuel stabilizer, but this additive is capable of much more. Sea Foam is a highly effective gasoline preservative stabilizer that both protects your vehicle while it's sitting and cleans the fuel system when it's running. 


Sea Foam is the most comprehensive cleaner for your vehicle. It cleans the fuel injectors, carb jets, and passageways by dissolving carbon deposits throughout your fuel system. While it's liquifying the varnish deposits and internal engine contaminants, it is also lubricating your intake valves, pistons, and cylinders. What really sets it apart from the competition is its ability to be used in any gasoline and diesel engines. 


While this gas preservative additive is applicable for any motor, it is not necessarily the best product for every job. Sea Foam is the most expensive option on our list, so people who don't want to spend too much money will probably prefer a different option. This additive also works the best with a vehicle you plan to keep running, so if you want a stabilizer for storing your fuel, there are better options out there.

Honorable Mention
STP Ethanol Fuel System Treatment

A bottle of STP Premium Fuel Stabilizer is one highly versatile product. Keep this liquid in your garage, and you’ll be able to put it to use not only in your car’s gas tank but also in your gas-powered tools, generators, lawnmowers, snow blowers, and more. Made with an all-season formula that works in both 2-stroke and 4-stroke engines, you can put this product to work in countless ways.


This formula helps keep fuel perfectly stable while also cleaning your fuel system, protecting against corrosion, and combating the water retention of ethanol fuel. The stabilizer’s ingredients clean and prevent deposits, both carbon and ethanol. It includes antioxidants that work to keep fuel fresh, and those same antioxidants also help you achieve quick, easy starts even after months of sitting unused. 


Just 8 ounces of this stabilizer can treat up to 20 gallons of gasoline, and you can adjust for smaller or larger fuel tanks as needed for any vehicles or tools you might have.

Honorable Mention
Lucas Oil Fuel Stabilizer

Lucas Oil Fuel Stabilizer is an efficient, safe product for keeping gasoline stable in unused tanks. It works on all two-stroke and four-stroke engines and with any grade of fuel. The formula is also really easy to remember: 1 ounce per gallon in the tank.


Our favorite thing about this fuel stabilizer is the way it cleans your entire fuel system while it sits idle. It ensures that your carburetor, injector, and pumps don’t experience any loss of performance due to corrosion or deposits. Winterized vehicles can be left alone for up to a year without suffering noticeably.


What keeps Lucas from the top spot is the somewhat high stabilizer-to-gallon ratio. Many other products, like STA-BIL, can be stretched further. Also, while the additive itself is top quality, the bottle isn’t and occasionally leaks while in transit.

Honorable Mention
Schaeffer Neutra Fuel Stabilizer

The Neutra Fuel Stabilizer from Schaeffer Manufacturing costs a bit more than the others on this list, but it’s worth it for convenience. Neutra works in gasoline, diesel, and ethanol engines, so if you spring for a gallon, it might be the only stabilizer you’ll need for years.


As a combination treatment/stabilizer, Schaeffer Neutra improves fuel efficiency by cleaning carburetors and injectors while it sits. In addition to scrubbing out deposits and particulates, it depresses the freezing point of water, which makes it a particularly good choice for winterizing vehicles in cold climates. The results you get from this product are almost immediate.


There are a few issues with Neutra. The packaging isn’t always sealed well, leading to some leaks, and both the 12-ounce and gallon sizes could use a longer nozzle. Its power also isn’t concentrated well. It takes an entire 12-ounce bottle to treat a full car tank, which can get expensive over time.

Honorable Mention
Mercury Quickstor Fuel Stabilizer

Mercury is well-known in the nautical world for manufacturing high-quality boat engines and outboard motors. Its Quickstor Fuel Stabilizer is a recommended treatment for nautical engines, but it also works wonders on cars, trucks, and other gasoline and ethanol engines.


The best thing about Mercury Quickstor is its concentrated power: 1 ounce works on 5 gallons of fuel, making this a potent, efficient treatment for your unused fuel. It makes winterizing your gas tank a snap, so you can move on to more involved seasonal chores.


Some drawbacks include the price, which is higher than average for a 12-ounce bottle, as well as the fact that it can cause performance problems if mixed with other additives. If you used a different brand last year, we recommend adding more gas to dilute it before applying this product.

Honorable Mention
Peak Blue Agri-Clean Liquid Fuel Stabilizer

Made just for diesel fuel, this particular stabilizer will both protect and enhance your fuel, offering a wealth of benefits. It’ll do more than your average stabilizer, giving you plenty of value with every use.


Peak Blue’s fuel stabilizer comes in a 32-ounce bottle, which is enough to treat 100 gallons of diesel fuel. Once mixed in with your fuel, it can help improve engine performance, restoring any lost injector functionality, and helping your engine start faster. You’ll experience smoother running, which in turn can also optimize your fuel economy and help you get more miles on every tank. And it’ll even reduce harmful exhaust emissions no matter what kind of diesel fuel you’re using.


There’s just one crucial detail to note before buying: this product is specifically formulated for diesel, but it’s meant for use in diesel-fueled agricultural and off-road vehicles. It’ll work best when used for tractors, ATVs, UTVs, and other tough or rugged vehicles, not your average passenger car.

Honorable Mention
Royal Purple Max-Clean Fuel System Cleaner and Stabilizer

This state-of-the-art formula is meant to enhance your fuel and lead to better performance when you hit the road — and it’s made specifically for vehicles.


With Royal Purple’s fuel stabilizer, you’ll be able to do a whole lot in one move. It’ll clean injectors, eliminating gunky buildup and deposits. It reduces engine buildup and lowers tailpipe emissions, doing good for your car and the larger environment. And it’ll even improve your horsepower and fuel economy. With this stabilizer, you can see around a 3 percent increase in your miles per gallon and see your horsepower increase by about 2 percent—rough idling, hesitation, and engine stalling will be problems of the past.


Some customers even say that this stabilizer was able to eliminate issues once used. Whether you drive a new or old car, it’s a great product to prevent and tackle typical engine or fuel system woes.

Honorable Mention
K100 Gasoline Fuel Treatment

If your biggest concern is water contamination, you’re going to want to grab a bottle of K100 Gasoline Fuel Treatment. This product is designed specifically to stop water contamination, preventing or resolving the phase separation that can happen when fuel sits unused. And this efficient and highly helpful fuel stabilizer can work on gasoline and diesel fuels, including LSD and ULSD varieties.


In addition to targeting water contamination, this product also offers a wealth of fuel system and engine benefits. Add it into your gas tank, and you’ll get perks like reduced emissions, improved mileage, easier starts, smoother idling, and more. It’ll increase your engine’s power and help you achieve faster acceleration. 


Besides lengthening the shelf life of your fuel, this stabilizer will also modify it, increasing atomization to improve the fuel-to-energy conversion process. And as a result, you’ll get impressive results when you do get behind the wheel or put your fuel to use once again.

Tips

  • If you're adding fuel stabilizer directly into your gas tank, be sure you add it before filling your tank. This will ensure you only use the desired amount of stabilizer, and the fuel pump will help mix the additive evenly throughout the tank.
  • The condition you keep your fuel and fuel stabilizer makes a huge difference. Make sure your containers are in a safe and dry storage area and that they are out of direct sunlight.
  • Always follow the company's suggestions when it comes to using fuel stabilizer. The amounts are important to ensure your fuel is protected and you are getting the most out of your purchase.
  • Be aware of what type of fuel you use before you buy fuel stabilizer. Some additives can be used with different types of fuel, while some only work with one. Be especially careful if you have a diesel engine, as most companies produce separate stabilizers specifically for diesel fuel. 

FAQs

Q: Should I use fuel stabilizer?

Using fuel stabilizer is entirely optional, but it has many benefits that might make it the right option for you. Using fuel stabilizer will keep your gasoline fresh while in storage and also cleans your fuel system from impurities and water buildup.

Q: Can fuel stabilizer fix old gasoline?

No, fuel stabilizer cannot convert bad fuel into good fuel. It needs to be added to good fuel, but it will keep that gasoline fresh.

Q: How long does fuel stabilizer stay good?

There’s no exact answer to this, but there are some things to consider. An open container won’t last as long as a sealed container—which will remain usable for a long time. Also, the climate that the container is kept in can negatively affect its longevity.

Q: When should you use a fuel stabilizer?

If you’re planning to put your vehicle into storage or know you won’t be driving it for some time, it’s time to add a fuel stabilizer. Additionally, if you’re keeping a gallon or two of gasoline stored in a gas can, you’ll want to add some stabilizer. A fuel stabilizer can offer protection and beneficial effects for as long as 24 months, ensuring gas is clean and safe to use even if it’s been stored for some time.

Q: Does fuel stabilizer really work?

Fuel stabilizers really do work. If you’ve ever left your car in storage or even checked out an old gas can full of fuel, you’ll notice that over time fuel becomes gummy and deteriorates, changing its composition and liquidity.

Q: Can you use too much fuel stabilizer?

It is possible to use too much fuel stabilizer. Make sure you’re reading the instructions for use before adding any stabilizer into your gas tank — you can find the recommended amount and learn how often you can use the stabilizer right on the bottle.

Final Thoughts

For overall protection and preservation, Star Tron Enzyme Fuel Treatment is the best fuel stabilizer. 

For customers who want a great product at a cheaper price, STA-BIL 22214 Fuel Stabilizer is an amazing option.