I bought my Stang used this summer. After 3 months I changed the oil and noticed small bits of steel in oil when I did an oil change. I put in a new Motorcraft filter and changed the oil. 3 months laters I changed the oil again hoping not to see as many steel shavings but there were still there. Should I be worried? Is there something I need to do to prevent further damage? My Stang seems to be running ok and I don't really beat it so I'm wondering what's going on.