BTW an extra 1/2 quart will not hurt anything, so I wouldn't worry about that. But I would take it to the dealer and make them change your oil and put a new drain plug in.TMMAR said:Thank you to all who replied. I tried a 13mm and it slipped. I believe the last oil change the dealer did stripped the bolt slightly and they must have had a gorilla working on it because it is extremely tight. They also overfilled the crankcase by about 1/2 quart. So much for going to the Goodwrench to get work done!!! ???