Wal-Mart is a JOKE. I don't know a damn thing about changing the oil and I'm 100% sure I am more competent than anyone there. I had 2 incidents with them. Once, they also left the oil cap off. 2nd time...they put the WRONG oil in and then told me I would have to pay for it to be redone. I threw major bitch fit with manager and got it done for free (like it should have been). I gave not been back to Wal-Mart for oil changes since!