10 Best Diesel Additives 2025 in the United States

The Archoil AR6500 Diesel Treatment is a solid choice for anyone looking to improve the performance and protection of their diesel fuel system. It combines multiple benefits in one product, including a strong cetane boost that helps your engine start easier and run smoother by improving fuel combustion. It also cleans and lubricates the fuel system, which is important for maintaining injectors and high-pressure common rail (HPCR) systems, potentially preventing costly repairs.

Additionally, it’s formulated to handle modern diesel fuel challenges, which can include issues like fuel gelling in cold weather and water contamination, thanks to its ability to stabilize fuel and disperse water. The fact that this two-pack treats up to 800 gallons makes it a good value for those who want to maintain their diesel vehicles regularly. The product is somewhat heavier and larger than some other additives, which could be less convenient if you prefer smaller bottles for storage.

With positive feedback from many users, this treatment is well-suited for diesel vehicle owners who want an all-in-one additive that improves power, protects fuel systems, and enhances fuel stability without having to buy multiple products.

Hot Shot's Secret EDT+ Winter Defense is a strong choice for anyone using diesel engines in cold climates. This 7-in-1 additive effectively prevents diesel fuel from gelling by reducing the size of wax crystals, allowing fuel to flow easily even down to -20°F below the usual freezing point. It also helps avoid fuel line freezes and ice formation, protecting your engine during harsh winter conditions, which is crucial for reliable cold starts.

Besides its anti-gel properties, it boosts the cetane rating by 7 points, which can improve engine performance and reduce smoke. The additive also improves lubricity by up to 32%, helping to protect fuel system components like pumps and injectors from wear. On top of that, it disperses water to prevent rust and corrosion, which is important for maintaining the fuel system's health. The injector cleaner function helps remove deposits inside and outside the injectors, contributing to better fuel efficiency and engine longevity.

Usage is straightforward: a small amount treats up to 200 gallons, making it easy to add during regular fueling, with a higher dose recommended in extreme cold. One potential downside is that it may be overkill if you live in milder climates or don’t often face freezing temperatures. Also, while it covers many needs, users looking for additives focused exclusively on one benefit, like only a cetane booster or injector cleaner, might prefer more specialized products. For winter diesel fuel protection combined with multiple benefits in one product, this additive offers a convenient and effective solution.

Hot Shot's Secret Diesel Extreme is a versatile diesel fuel additive that targets multiple common issues faced by diesel engines. It effectively cleans the entire fuel system, including injectors, valves, and pistons, helping to remove stubborn deposits that can reduce engine efficiency. This cleaning action can lead to smoother engine performance and potentially better fuel economy.

The product also boosts cetane levels by up to 7 points, which improves combustion, resulting in more power and reduced emissions like less frequent diesel particulate filter (DPF) regenerations. Additionally, it includes a non-alcohol-based water dispersant and rust inhibitors that help protect the engine from moisture damage and corrosion, which is important for maintaining reliability over time. The additive is concentrated and easy to use, requiring just 8 ounces per 20 gallons of diesel, making it convenient to apply during regular fill-ups or every 6,000 miles. It is also unscented and liquid, so it blends easily with fuel without noticeable odor.

While it covers many bases like injector cleaning and cetane boosting, it does not specifically mention anti-gel properties, which could be a consideration in very cold climates. Diesel vehicle owners looking to maintain engine cleanliness, improve fuel efficiency, and protect fuel system components will find this additive well suited for their needs. Those in colder areas or needing specialized anti-gel protection might want to supplement with another additive.