10 Best Oil Additives To Stop Leaks 2025 in the United States

Bar's Leaks OS-1 Seal Engine Oil Burning/Leak Repair is a versatile product designed to address oil leaks and reduce oil burning in a wide range of gasoline and diesel engines, including turbocharged and hybrid models. This product is suitable for various vehicles such as cars, trucks, vans, and SUVs, as well as heavy-duty applications like tractors and boats. Its universal fit makes it highly compatible and easy to use for many different engine types.

One of its key strengths is its ability to renew worn valve seals and guides, which can significantly reduce blue exhaust smoke and oil consumption if your vehicle is not consuming more than one quart of oil per day. Being made in the USA adds a level of trust and reliability to its quality. The product may not be as effective for extremely high oil consumption cases, and its concentration and combination of additives may not be suitable for all engine conditions.

Bar's Leaks OS-1 is a solid choice for those looking to stop oil leaks and reduce oil burning in a variety of engines, provided the oil consumption is moderate.

The Lucas Oil 10009 Transmission Fix is a highly regarded transmission problem-solving additive designed to stop leaks and extend the life of transmission fluid. One of its major strengths is that it does not contain solvents, making it a safer option for your vehicle's internals. You can easily add it to your existing transmission fluid without the need to drain any out, which is convenient and saves time.

This product is especially effective for motor homes and commercial vehicles, and it can extend the life of your transmission fluid up to four times longer, reducing the need for frequent fluid changes. It also offers additional protection to planetary gears and improves shifting ease in worn transmissions. However, it's important to note that it is not recommended for CVT transmissions and dual-clutch vehicles.

Be mindful that in larger or heavily worn transmissions, you may need to use a second bottle for optimal results. For smaller vehicles, a smaller 12 oz. bottle is recommended. With its strong market presence, Lucas Oil 10009 Transmission Fix is a reliable choice for those looking to maintain or improve their vehicle’s transmission performance.

The Lucas Oil 10018 Hydraulic Oil Booster & Stop Leak is presented in a 1-gallon pack of four. This product is manufactured by Lucas Oil and is designed for use in various hydraulic systems, such as automatic transmissions, power steering units, and more. This additive boasts several essential features for stopping leaks: it contains seal conditioners to rejuvenate old seals, viscosity modifiers to maintain an optimal oil thickness, and detergents and dispersants to keep the hydraulic system clean.

The product is made from materials like Polytetrafluoroethylene and Molybdenum Disulfide, which can aid in reducing wear and tear in hydraulic systems. It has a substantial package weight of 32.6 pounds, and the considerable volume of 4 gallons could be more than enough for extensive use. However, its larger package size might be cumbersome for some users to handle.

Additionally, the extensive range of compatible applications makes it versatile. While it is not a new product (released in 2012), it remains in production, suggesting a consistent demand. The oil additive stands out in its category, ranking #137 in Engine & Oil Fluid Additives on Amazon. Despite its strengths, potential users should ensure compatibility with their specific systems to avoid any mishaps. Its weight might also be a concern for those looking for a lighter option.