hi sages- would like to know crankcase oil drain plug size. about to do first oil change in first volvo. i have sae size sockets and a basic set of sockets of metric size. drain bolt is on tight and i dont want to round the points with a wrong size or a 12 point socket. figure proper socket is a 23 or 24 mm shallow six point socket. told that 25 mm is same as one inch socket but the one inch seems a little loose.is the exact size a 23 or 24 mm. these sizes are 1/2 inch drive. guessing proper method is to use a breaker bar or a 1/2 inch drive ratchet on the socket. would appreciate your best advice . thanks tons oldduke ps- using 5 qts quaker state 10- 30 oil and a mann filter when i can get the oil plug out.