Oil stop leaks are designed to revitalize gaskets and seals to minimize gaps that cause leaks. However, if you have a large hole or a lot of engine damage, an oil stop leak will not solve the problem.

Does engine stop leak actually work?

Today, the best stop-leak additives are actually absorbed by the seals and then expand the seals, returning them to their original shape, flexibility and size. ... While the new formulas will stop those leaks in many situations, they aren't a permanent solution. The leaking seal will, sooner or later, need replacing.

How long does Oil Stop Leak last?

So how long can you expect them to last? It depends. If the leak is mild to moderate, we've had customers run 10,000-50,000 miles with no further issues. If the leak is more severe, or on the edge of becoming severe, the repair might last a shorter duration.