Mannol 9423 Engine Oil Leak Stop 300ml is a high-performance additive designed to eliminate engine oil leaks and prevent future ones. Specially formulated for petrol and diesel engines, it revitalises hardened or shrunken rubber seals, gaskets, and O-rings without causing any damage. This treatment helps restore sealing performance, reduces oil consumption caused by leaks, and minimises smoke from burning oil. Ideal for older engines or those with minor leaks, it’s compatible with all mineral, semi-synthetic, and synthetic oils. Simply add it to your engine oil—no need for draining or mechanical repairs. Safe, effective, and easy to use, Mannol Leak Stop is your go-to solution for maintaining engine cleanliness, reducing wear, and extending engine life.