The last time I changed the oil on a 83 Cougar the oil pan drain plug hole was stripped so I put one of those oversized drain plugs on it, if I remember I tightened one end down and on the outside it had another nut, do you just loosen this outside nut to drain the oil and leave the other one where it's at? It's been a while and this is relatives older car. If anyone else has used these plugs please comment. Thanks.