10 Best Oil Leak Additives 2026 in the United States

The ATP Automotive AT-205 Re-Seal Stops Leaks is a versatile and effective oil-leak additive that boasts a professional strength formula designed to quickly seal leaks. One of its notable strengths is its compatibility with a broad range of fluids, including conventional and synthetic oils, ATF, gear oil, power steering fluids, and hydraulic oil. This makes it a flexible choice for various systems such as engines, transmissions, power steering, differentials, and hydraulic systems.

The product excels at conditioning rubber seals and gaskets, helping to rejuvenate them without over-swelling or breaking them down, thanks to its formula that excludes petroleum distillates. This feature ensures that the seals maintain their integrity longer, preventing future leaks. The 8-ounce bottle is convenient for treating up to 6 quarts of fluid, although users may need to adjust the amount depending on their specific needs.

In terms of ease of use, the compact design and clear instructions make it user-friendly even for those who aren't mechanically inclined. On the downside, the product's effectiveness can vary depending on the size and severity of the leak, with more significant leaks potentially requiring professional attention. Despite these minor drawbacks, the AT-205 Re-Seal is a strong option for anyone looking to address minor to moderate leaks in a variety of automotive systems.

Lucas Oil 10279 Engine Oil Stop Leak is a versatile additive compatible with petroleum, semi-synthetic, and full synthetic motor oils, making it suitable for most vehicles including cars, trucks, and motorcycles. It gently renews worn seals without harmful solvents or risking engine damage, which helps reduce oil leaks and lowers engine noise.

This product is user-friendly as it simply mixes with existing engine oil, avoiding complicated application steps. It effectively handles small to moderate leaks, though major or severe leaks may require mechanical repairs beyond what an additive can fix. The additive is balanced to raise oil pressure and slow oil consumption, serving as a temporary solution rather than a permanent fix.

Lucas Oil is a reputable brand in automotive care, adding confidence in the product’s reliability. The 1-gallon size may be larger than needed for some users, which can affect cost-effectiveness if you have a smaller engine or minimal leaks. This stop leak additive is a good choice for maintaining engine seals and reducing minor oil leaks without hassle but should not replace professional repairs for severe leaks.

The Lucas Oil 10278 Engine Oil Stop Leak is designed to be a universal-fit additive that helps reduce and seal oil leaks in engines. One of its strong points is compatibility—it works with most automotive engines, including UTVs, making it versatile for many users. The product is known for effectively conditioning seals, which can help rejuvenate old or worn gaskets and reduce leaks, especially smaller ones.

The concentration of additives in the formula is balanced to work without causing sludge or damaging engine parts, which is important for maintaining engine health. Users find it easy to use, simply adding it directly to the engine oil, with no complicated steps needed. Lucas Oil has a solid reputation in the automotive industry, and this product has received positive reviews, reflected in its good customer rating.

While it can help with minor to moderate leaks, it’s not a fix for large or severe leaks and shouldn’t replace proper mechanical repairs when those are required. Also, some users note that results may vary depending on the condition and age of the engine seals. If you want a reliable, easy-to-use stop leak additive from a trusted brand for small leaks and routine maintenance, this product is a good choice.