10 Best Engine Additives 2025 in the United States

The Chevron Techron Concentrate Plus Fuel System Cleaner is a high-quality additive designed for gasoline engine fuel tanks. As a concentrated formula in a 20 oz. bottle, it aims to improve engine performance by reducing rough idles, engine surges, hesitation, and spark plug fouling, making it a versatile option for those experiencing such issues. Additionally, it promises to enhance cold start performance and fuel stability for up to a year, which can be particularly beneficial for users in colder climates or those who do not drive frequently.

The product is unscented and comes in a liquid form, making it easy to administer into the fuel tank. Chevron, the brand behind this cleaner, is well-regarded in the automotive industry, further adding to the product's credibility. While performance claims are promising, they may vary based on individual engine conditions and usage patterns. For those looking for a reputable and effective solution to maintain their gasoline engine's fuel system, this product is a solid choice, although it's wise to manage expectations regarding the degree of improvement one might experience.

Lucas Oil 10003 Fuel Treatment is a versatile additive designed for both gasoline and diesel engines, making it a solid choice if you want one product to handle different fuel types. It works by cleaning and lubricating critical parts like fuel injectors and carburetors, which helps improve your engine’s performance and fuel efficiency. Many users report better mileage and smoother acceleration thanks to its ability to reduce harmful deposits and neutralize contaminants like sulfur. It also helps protect engine components from rust and corrosion, potentially extending their lifespan.

The product meets federal low sulfur standards for diesel engines, indicating it’s safe and compliant for modern use. Its universal fit means it can be added to nearly any vehicle without compatibility worries. While some might prefer additives specifically designed for either gasoline or diesel only, this one aims to cover both, which is convenient though more general in approach.

If you want to improve fuel system health, boost mileage, and reduce emissions with a single, easy-to-use fuel additive, Lucas Oil 10003 is a dependable option that has stood the test of time since 2005 and is well-regarded by many users.