10 Best Fuel Additives 2025 in the United States

The Chevron 65740-CASE Techron Concentrate Plus Fuel System Cleaner is a highly rated fuel additive designed to clean and protect the entire fuel system, including fuel injectors, carburetors, intake valves, and combustion chambers. It is suitable for various fuel types, and users can find more specific recommendations in the vehicle owner's manual. The product claims to restore lost power and fuel economy, reduce engine issues like rough idling and hesitation, and improve cold start performance.

Additionally, it enhances fuel stability for up to a year, making it a versatile additive for maintaining engine health. This pack of six 20 oz. bottles is an economical choice for regular maintenance. The product is made in the USA. Users should be mindful of the concentration and dosage instructions to avoid potential engine damage. The long-standing reputation of the Chevron brand in the automotive industry adds to its credibility.

While the benefits are clear, the product's efficacy may vary depending on individual vehicle conditions and usage patterns.

The Sea Foam SF128 Motor Treatment is a versatile fuel additive compatible with both gasoline and diesel engines. It effectively cleans fuel deposits and sticky residues from various engine components, such as injectors and carburetors, improving engine performance. One of its standout features is its ability to stabilize stored fuel for up to two years, which is particularly beneficial for vehicles or equipment that are not used frequently.

This helps in maintaining fuel quality and preventing the formation of gum and varnish. The product also offers high-temperature upper cylinder lubrication, protecting the fuel system from wear and corrosion. Additionally, it is made from petroleum-based ingredients without harsh detergents or abrasive chemicals, reducing the risk of engine damage. The more you add, the better the cleaning effect, according to the manufacturer.

Weighing 3.5 pounds and measuring 10.5 x 7.5 x 5.5 inches, the product is relatively easy to handle and store. However, users should be aware that the packaging may vary. With a high ranking in fuel system tools, it's clear that many users trust and rely on Sea Foam SF128 for their fuel treatment needs. Potential buyers should consider that its cleaning effectiveness might require larger quantities for optimal results, which could increase usage costs over time.

The Sea Foam Marine PRO Marine Fuel System Treatment MP20 is a comprehensive solution for maintaining and enhancing marine engines. It works well with both 2-stroke and 4-stroke gasoline engines, making it versatile for various types of watercraft. The product aims to clean fuel injectors and carburetor jets, lubricate upper engine areas, and reduce long-term engine wear, which are all significant for maintaining engine health and performance. Additionally, it helps prevent corrosion caused by ethanol and water, which is crucial for marine environments.

One of its standout features is that it can stabilize tank fuel for up to two years, providing peace of mind for seasonal boaters or those who store their craft for extended periods. The product has received positive feedback from users, reflected in its high customer rating of 4.8 out of 5 stars based on 716 reviews. However, it ranks #79 in Fuel Additives, indicating there are other popular options available in the market. The pack of six 20 oz bottles offers good value for maintaining multiple engines or for long-term use.

The brand, Sea Foam, is well-regarded in the automotive industry, which adds to the product’s credibility. Despite minor drawbacks, the Sea Foam Marine PRO Marine Fuel System Treatment MP20 is a reliable and effective fuel additive for marine engines, offering comprehensive maintenance and performance benefits.