My wife has a 2005 Pontiac Vibe, engine code from the VIN, 8th character, is the number 8, which indicates it holds 3.9 qts of oil. The threads inside the oilpan for the drain plug are screwed up as the bolt tightens up about two turns before it seats. What size tap do I need to clean this mess up? K Mart has been changing the oil and there is blue RTV anound the oilpan drainplug hole. The head of the bolt is 14 mm as best as I can tell. Is there a better way to proceed? Thanks notapromike