Quick question...I was planning on switching over to Mobil 1 synthetic after a few oil changes and was going to go with the factory stated 5W-30W. I just moved and low and behold, at the place I took, the old tenant left behind a case of Mobil 1 0W-40W (appears fairly new). Any problems you guys can think of NOT to use this?? (ps. By the way, I called the guy that had the place and his wife says it must have been for thier boat which they sold when they moved..she said keep it or toss it). Thanks for your time.

If you can't trade it in for xW-30 or sell it to your neighbor with the Porsche, I would just go ahead and use it.

That is one gift horse that you want to take a good look at. Check the seals on the caps. It could be a sneaky way to get rid of old oil.