Oil Leak Crankshaft
 

I had a mechanic replace both lower front arms today on my 2004 Boxster S ,I asked him to see if he could see where I had an oil drip coming from.
He said it looks like it is coming from the crank shaft gasket and said it is a big job to replace this with the gasket not being expensive but the labour time to do the job is .
He said it would cost about £700 to do. He suggested buying Stop Leak and put it in with the oil and this may stop the leak.
Has anyone ever tried this?