The noise could be that the machine is slightly out of timing and needs to be adjusted. This getting out of time can be caused by a clogging of thread or even by a dull needle trying to penetrate the fabric. So if all the other hints don't fix it, you may need to have it checked by a reputable repairman. I am please to learn about the oil wick. My Brother machine seems to have a little felt pad in the center of the bobbin case and I am glad I left it alone.