Best Fuel Additives: Maximize Your Fuel Efficiency with These Top Picks

Consider these fuel additives to improve efficiency in gas-powered vehicles.

byHank O'Hop|
best Fuel Additives Reviews and Buying Guide


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There's simply no replacement for the real thing. Fuel additives can get you pretty darn close in many cases, though. Not everyone has the means to tear down an engine to clean things up, high-test fuel isn't around every corner, and it's not like the price of gas makes it easy to flush the system anyway. Instead of driving yourself nuts, you can use fuel additives to get the job done. It's not wise to just run off with only that bit of knowledge. You see, we've wandered into the territory of snake oils and magic elixirs. Everyone's got some miracle product you just won't believe. You know, the kind that you try and come to find, the only thing you can't believe is how good someone could be at selling duds. That's what I'm here to help you avoid. There are great fuel additives on the market, and I'll help you find them. 

Best Overall

LUCAS LUC10013 Fuel Treatment

Formulated for both gas and diesel engines. Features strong compounds that clean and lubricate the fuel system for maximum performance. Blend of additives that gives the fuel system maximum efficiency.
  • Does an excellent job of cleaning internal components 
  • Can be used in gas or diesel applications
  • Replaces lead in older engines 
  • Contains chemicals that can be harmful to the environment
  • Slight contact with this additive causes skin irritation 
Best Value

Red Line Complete Fuel System Cleaner

Designed to clean and prevent corrosion in gas engines. Contributes to 100 percent fuel system efficiency after the first clean.
  • Prevents buildup of gum, carbon, and varnish in the fuel system 
  • Promotes fuel stability 
  • Safe for continuous use 
  • Reduces need for high octane gas
  • Comes in small size that may not be enough to treat large engine system 
  • Not suitable for diesel fuel 
Honorable Mention

Star Tron Enzyme Fuel Treatment Concentrate

Multifunctional and uses unique enzyme technology to enhance fuel efficiency. Features universal formulation that can be used with any gasoline engine or any ethanol-based fuel. Perfectly cleans fuel delivery system, which aids in fuel economy.
  • Cures and prevents ethanol fuel problems for better engine performance 
  • Stabilizes gasoline for up to two years 
  • Not harmful to your system in case of an overdose
  • Bottle does not allow for spill-free pouring 
  • Expensive

Summary List

Best Fuel Additives Reviews & Recommendations

Best Overall: Lucas LUC10013 Fuel Treatment


Does an excellent job of cleaning internal components

Can be used in gas or diesel applications

Replaces lead in older engines


Contains chemicals that can be harmful to the environment

Slight contact with this additive causes skin irritation

Lucas offers a fuel treatment additive that cleans, lubricates, and neutralizes poor quality fuel. It doesn’t contain alcohol or solvents, and is made of heat-resistant oils to maintain its effectiveness during extreme pressure conditions in the engine. As for the formulation, the engine oil features fuel injector cleaners that remove sediments and sludge, which often lead to spark plug misfires. It also contains fuel conditioners that neutralize low sulfur problems in the fuel system. This additive works on both gas and diesel engines, and is known to improve the octane rating of gas. It can also be used on both fuel-injected and carburetor engines, and works well on locomotives, marine, and non-road engines. Since the product keeps your fuel system clean and lubricated, you can expect better fuel economy, lowered emissions, and less wear on the critical engine components.

Unfortunately, the product has a strong formulation with some chemicals that are considered to be harmful to the environment. You should remember to wear gloves when handling it, as even slight contact can cause skin irritation. It can also stain parts of your car’s paint body with accidental spills. We recommend that you use it with a funnel to avoid spills.

Best Value: Red Line Complete Fuel System Cleaner


Prevents buildup of gum, carbon, and varnish in the fuel system

Promotes fuel stability

Safe for continuous use

Reduces need for high octane gas


Comes in small size that may not be enough to treat large engine system

Not suitable for diesel fuel

This fuel system cleaner offers an alternative to buying high octane gas. This is because it has a patented formula that removes carbon deposits from the engine. It also does a good job at cleaning deposits such as gum and varnish from the carburetors, injectors, valve, and combustion chamber. What’s more, the fluid features a concentrated blend of high- and low-temperature detergents to make it stable and effective under extreme engine conditions. Not only is it a good cleaner, but it also contains a synthetic lubricant that will reduce friction in the upper cylinder. There are no harmful ingredients in the formulation and it, therefore, won’t be toxic for your engine or the environment if used continuously. Lastly, the fluid comes in a clear bottle that’s easy to use, even without a funnel.

The main downside of this cleaner is that it comes in a small bottle and you have to keep buying more if you want to reduce the deposits in your fuel system. You may also have to use more than one bottle if you have a large fuel tank. It’s only formulated for gas engines and, therefore, not all vehicles and heavy-duty equipment can benefit from it.

Honorable Mention: Star Tron Enzyme Fuel Treatment Concentrate


Does an excellent job of cleaning internal components

Can be used in gas or diesel applications

Replaces lead in older engines


Contains chemicals that can be harmful to the environment

Slight contact with this additive causes skin irritation

The Star Tron Fuel Treatment is a strong fuel system additive that stabilizes gas (including ethanol blends) for up to two years. It has antioxidants that prevent fuel separation. A unique blend of enzymes in its formulation helps to improve fuel combustibility and, in turn, provides more engine power and improves fuel economy, even if the engine was sitting idle throughout a season. The product also features deep cleaning action that removes gum, carbon, and varnish from the tanks to the injectors. This eventually makes your engine start easily and run smoothly. It goes further to break down excess water and sludge to smaller particles that can be burned away when the engine is in operation.

The drawback of the product is that it’s only suitable for gasoline engines. You'll also need a funnel to pour out the contents since the container doesn’t allow for spill-free pouring. Moreover, it’s a bit expensive in comparison to most one-gallon fuel additives.

Best for Diesel Engines: Opti-Lube XPD Formula Diesel Fuel Additive


Cleans and promotes fuel stability

Keeps crystals from clogging fuel system in cold weather

Treats up to 512 gallons of fuel

Comes with extra bottles and pump



Limited application compatibility

The Opti-Lube XPD Formula Diesel Fuel Additive is specially formulated for diesel-powered engines. This product is available as a 1-gallon bottle with accessories, including a hand pump and two empty 8-ounce bottles. There’s enough additive included to treat up to 512 gallons of fuel. It’s recommended to add this formula to your vehicle while refueling at the gas station pump. This will ensure that the gel is mixed properly with your fuel and that it won’t separate or fall out of solution. During colder months, this formula helps prevent large, filter-plugging crystals from forming in your fuel. Make sure to follow the instructions on the back of the bottle to improve your vehicle's fuel economy, reduce deposits and emissions, and prevent rust and corrosion.

The potential pitfall of Opti-Lube XPD Formula Diesel Fuel Additive is its price point. But it can treat up to 512 gallons, so it’s likely a great purchase for the premium price. This additive is formulated only for use with diesel-powered vehicles.

Most Versatile: Helix Racing Products 5-in-1 Ultimate Fuel Additive


Cleans, protects, and boosts octane

Works with two and 4-stroke engines

Can be used in fuel injected or carbureted engines


Easily damaged in shipping

Limited to gas engines

The Helix Racing Products 5-in-1 Ultimate Fuel Additive is a highly reliable and versatile product. This additive is designed to work with both 2-stroke and 4-stroke engines. It has been proven to eliminate water from fuel systems and stabilize fuel for up to two years. The product cleans injectors, carburetors, and fuel system components. It also boosts octane by up to two points. An 8-ounce bottle of this fuel additive can treat up to 16 gallons of fuel. The product is specially formulated from complex, bio-based compounds that alter burn chemistry for a more complete combustion. Regular use of this additive results in more power, better mileage, and a cleaner environment. The trustworthy product is made by a reputable automotive manufacturer.

Some customers have reported damaged packages upon delivery. Make sure to inspect your bottle for any dents, rips, or tears, and reach out to the company about a potential refund or replacement if you notice any damage.

Best for Marine Engines: STA-BIL 360 Marine Ethanol Treatment and Fuel Stabilizer


Cleans engine and stabilizes fuel

Can be used in two and 4-stroke engines

Withstands even the harshest marine engines


Quality control can see some improvements

Limited to marine use

The STA-BIL 360 Marine Ethanol Treatment and Fuel Stabilizer is a great fuel additive for marine environments. This product helps prevent corrosion above and below the fuel line where no other additive can. It provides ultimate treatment and protection against ethanol-blended fuels. It’s a proven product that stabilizes fuel for up to one year. The product will not only help to improve power in your vehicle, but also improve your fuel efficiency. The fuel additive is more concentrated than comparable products, so it can hold up in even the harshest marine environments. It makes a great addition to your boat, jet ski, or any other watercraft. The treatment rate is 1 ounce to 10 gallons of fuel. It’s available in bottles ranging from 8 ounces up to 1 gallon.

One issue with the STA-BIL 360 Marine Ethanol Treatment and Fuel Stabilizer is its reliability. Some customers have reported issues with a poor aluminum seal on the bottle. If you notice that the bottle is leaking upon delivery, reach out to the company regarding a potential refund or replacement.

Best Octane Booster: Torco Fuel Accelerator


Significantly boosts fuel octane

Safe for use with emissions equipment

Can save improve engine life and improve power


Special considerations required for storage


Torco fuel accelerator is tough to beat in the octane booster segment. For one, it actually works, which puts it above a lot of the snake oils out there. Not only does it work, it boosts octane by a considerable amount. One 32-ounce bottle can basically convert 92 to 102 octane. Don't worry if that's way more than you need, though, as you can easily divvy up the bottle to last much longer with lower octane values. It's also a thoughtfully designed mixture that won't harm the catalytic converters or O2 sensors on street-legal vehicles.

As for the drawbacks, Torco is a bit tough to store due to its sensitive nature, and you need to think about where you'll keep it. It's also expensive, which is ultimately going to push consumers to other options.

Our Verdict on the Best Fuel Additives

For a high-quality fuel additive, consider the LucasLUC10013 Fuel Treatment, formulated for both gas and diesel engines, or the Red Line Complete Fuel System Cleaner, which contributes to 100 percent fuel system efficiency after the first clean.

Fuel Additives Buying Guide

The list above is great at a glance for those who know what they're after. Others might not find it so useful because they don't know exactly what they need. That's all right. This section of the buying guide will help you decide which fuel additive you need with just a few tips. 

Types of Fuel Additives

Fuel Treatments

Gas treatments are formulated with polyisobutene, and for that reason are cheap and widely available. They help improve the quality of gas by getting rid of harmful carbon deposits for cleaner emissions and breaking down water particles that can dilute the fuel. 

Fuel Injector Cleaner 

Fuel injector cleaners are an upgrade from gas treatments since they contain polyetheramine (PEA), which is one of the strongest cleaning agents. It also cleans more parts in comparison including the direct fuel injectors. The compound also removes clogs and carbon buildup in other parts of the fuel system to further improve overall health of the system. 

Fuel Stabilizer 

You can expect the quality of fuel to diminish over time if your vehicle is left idle for a season or if the fuel is in storage. Fuel stabilizers work to maintain the quality of the fuel by absorbing water and slowing down oxidation and chemical breakdown of the fuel. It also keeps fuel fresh for a relatively long time if it's in storage. 

Octane Booster 

While octane boosters aren’t formulated with the strongest cleaning agents, they do a good job of increasing the octane level in the fuel which can help clear out some carbon. Octane boosters are used to effectively raise octane levels of pump fuel. This is necessary with some high-performance builds that require higher octane levels due to a number of factors, such as high boost levels or high compression. Not all engines need octane boosters, and running one in an engine that does not need it can have adverse effects. It is important to study your application specifically to determine if you need this additive. 

Key Features

Fuel Compatibility

Some manufacturers make fuel additives that are specific to either diesel or gas engines. You can also find a multifunctional product that works for both. It’s important that you choose a product that’s compatible with your engine’s fuel to avoid corrosive chemical reactions, and damaged rubber seals that will result in engine failure. Also, consult your owner’s manual on what types of formulations or ingredients you should avoid for your engine. 


Fuel additives come in different sizes from 11-ounce bottles to large 5-gallon jars. If you don’t like to hoard car care products in your garage, you can go for a small bottle with just the right amount to treat your engine. However, there’s an upside to buying larger quantities: You can treat multiple vehicles or save money in the long run if it comes with a reasonable price tag. 

EPA Approval 

Prioritize fuel additives that have an EPA (Environmental Protection Agency) label, meaning that they comply with environmental regulations. Such a product typically works by dissolving carbon deposits in the fuel to reduce exhaust smoke production and harmful carbon emissions into the atmosphere. 

Fuel Additive Pricing 

​​Since such a broad range of different products qualify as fuel additives, it's hard to say an exact price you can expect to pay. Several factors come into consideration when determining the cost of a product. The type of additive, branding and the amount are three major factors that can dramatically change the sticker price. However, most small bottles will list for $30 or less. Buying a case of several small bottles or containers with more of an additive can easily drive the price up, exceeding $100 in some instances. 


Q: Do fuel additives actually work?

A. Yes. Fuel additives do work. They can only do so much, though. In some cases, tearing an engine down to clean or replace parts or switching to a different fuel will be the only option.

Q: When should I add the additive?

Gas treatments work best when they are added to the fuel tank first, before combustion. This means if you want to add a fuel additive, you should do so before you add any more gas to your vehicle. Just put in the recommended amount even if your tank is not empty.

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