Best to get a rubber replacement plug which, when inserted and tightened, expands to prevent leakage. Canadian Tire sells them, under $10.
Helicoil used for cases, like spark plug holes, where you wish to end up with the original thread size. This not required with oil drain hole as there are many aftermarket devices that self thread into damaged threads. These are usually used when oil pan can be easily removed, since you don't want metal filings remaining in the oil pan.
