Stop-leak products contain particles that are designed to find and fill small holes or gaps in an engine's components. This can help to prevent or reduce leaks and restore engine performance.

There are two main types of stop-leak products: temporary and permanent. Temporary stop-leak products are designed to seal leaks temporarily, while permanent stop-leak products are designed to create a more long-lasting seal.

Most automotive stop-leak products are safe to use, but it is important to read and follow the manufacturer's instructions carefully. Some stop-leak products may contain chemicals that can be harmful if they are not used properly.

When choosing an automotive stop-leak product, it is important to consider the type of leak you have, the size of the leak, and the type of engine you have. It is also important to read and follow the manufacturer's instructions carefully.