I have a small oil leak on the A3, which I eventually tracked down to the oil cooler gasket, and because that is a pig of a job to replace I've been looking for a simple fix. Wynn's Engine Stop Leak seemed like a good idea. The label states that one should simply pour the content into the engine oil (after enough oil leaked out - DO NOT overfill your engine) and in about 200 miles the leaks will miraculously stop. 500 miles later there is still no sign of anything happening, other than oil leaking out at the same rate.