Quick answer
Yes, additives with seal conditioners can reduce or stop minor leaks by softening and swelling hardened gaskets. But they won’t fix major tears or severely damaged seals—those need mechanical repair.
Detailed answer
When engine seals age, they lose elasticity, forming small gaps that let oil seep. An additive works by rejuvenating those seals—like moisturizers for rubber—closing up the cracks. This can be effective on older cars or ones that sit idle for long periods. However, if your leak is due to a major seal failure or a broken gasket, no additive can rebuild that. Look for products specifically labeled “stop leak” or “seal reconditioner,” and follow the instructions for best results.
