10 Best Oil Leak Additives 2025 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.

Bar's Leaks Jack Oil with Stop Leak is designed to stop current leaks and help prevent future ones in floor and bottle jacks, as well as snow plow fluids. It stands out for its broad compatibility, working with all petroleum-based, mineral, and synthetic oils, which means you can use it with most common jack fluids without worry. The product is non-corrosive, non-clogging, and doesn’t foam, which helps maintain smooth operation and protects seals without causing damage. This suggests it conditions seals gently, potentially extending their life.

The 12.5 oz bottles (sold in a pack of two) offer a decent volume for treating multiple jacks or repeated applications. It’s easy to use since it comes ready to pour, making it convenient even if you're not mechanically inclined. The brand Bar's Leaks is well-known in the automotive maintenance space, and with over 3,000 customer ratings averaging 4.6 stars, it has a strong reputation for effectiveness. However, this product is specifically targeted for jacks and similar hydraulic equipment, so it may not be the best choice if you’re looking to fix leaks in other engine oil systems or larger automotive components.

While it claims to stop and prevent leaks, very large or severe leaks might still require professional repair rather than just additive treatment. This additive is a solid choice if you need an easy, reliable product to maintain or fix minor leaks in hydraulic jacks and related equipment, especially if you prefer a trusted brand with positive user feedback.

The Lucas Oil 10118 High Mileage Oil Stabilizer is well-regarded for its compatibility with various automotive engines, making it versatile for different vehicles. One of its key strengths is its ability to condition seals, which can help prolong the life of engine components and potentially reduce small oil leaks. This product is particularly effective for high-mileage engines, as it raises oil pressure and helps eliminate noises, emissions, and excessive oil consumption associated with worn engines. Users have reported significant improvements in engine performance and longevity after using this additive.

The concentration of the additive is designed to provide thorough lubrication to all internal parts, minimizing wear and preventing sludge build-up, which is a common issue in older engines. The ease of use is another highlight, as it comes in a straightforward bottle package that can be easily added during regular oil changes. Lucas Oil, the manufacturer, is a well-known and reputable brand in the automotive industry, adding to the product's reliability.

While it is effective in managing smaller leaks and improving engine performance, it may not be a comprehensive solution for very severe leaks. Additionally, the product's effectiveness may vary based on the specific condition of the engine. Customer satisfaction remains high despite these points.