Re: Rear main seal leak!!!
Back in the late 1970s, I used to do a fair amount of work on BMW Motorcycles and they had the same problem with Mobil 1 Motor Oil. The Customer had no leaks with Petroleum based and when they poured the Mobil 1 in, they leaked out of every Circular Silicone Seal. I was told that Mobil re-formulated the oil, to stop the problem.