i think it takes 4.5 quarts. as far as the o-rings, when you bought the oil filter, it should have came with two o rings. a big one and a smaller one. The oil filter you got should have been WIX (napa gold) or motorcraft, otherwise you have to deal with twisted filters, etc. after you drain the oil from the drain pan, you have the filter assembly. it takes a torx (i think....either that or a hex) to unbolt the drain plug for the oil filter. it's the silver bolt in the middle. that will drain the oil from the filter so you don't take the thing down and have oil everywhere. Once you take that bolt out, there is a little o-ring on the bolt, near the head. that has to get replaced with the new one of the same size. make sure you oil it before you screw it back in. once you unscrew that, you can unscrew the housing for the filter. i guess there is a tool you can buy....i got a 6-in-1 wrench at walmart. take that thing down and then you take out the old filter. on that housing, toward the head, is a big o-ring. replace that with a new one and oil it. put it all back together and you should be good to go.