I am looking for what oil to use to maybe help cut down on an oil leak. The car has the gm 3.8 v6 in it and I guess it is notorious for rear main seal leaks. It was fixed once around 25,000 miles and it may be leaking again as there are a couple drops on the ground, nothing like it was leaking before though. The car has ~65,000 miles on it. Not really wanting to pay for the rear main seal to be replaced, the first time was under warranty. So would using something like castrol high mileage help or anyone have any suggestions on what other type of oil my help the leak a little bit? Right now I am using 10w-30 castrol gtx.