LeakLock is an oil additive that gives tired rings a new lease of life. The stuff makes the simmer rings supple again and makes them 'swell' just a bit. That may mean the end of the eternal drop that always finds its way out through the rear crankshaft seal, but the product is not a panacea for seal failure. What it can be the ideal solution for is solving leaks from wheelhouses. From our own experience we measured a 'repair time' of two years.
Available through specialist car stores