Bookem, my STRONG suggestion:
Buy yourself an OVERSIZE oil drain plug at your automobile parts and accessories store; I'd recommend an M12-1.5 OVERSIZE product for your application (retaining the original pitch exploits any possible remaining thread material).
The tapered, self-tapping threads and slightly larger diameter of an oversize oil drain plug can rehabilitate the hole for a lasting seal and fix for the problem.
An oversize oil drain plug costs only a few dollars, and--if it seals, you have a permanent repair.
If it does not seal, you're no worse off than when you started.
I've had MIRACLE CURES with oversize oil drain plugs, although the procedure seems controversial in the hearts and minds of some, who insist upon inserts, drilling-and-tapping, welding, or other techniques.
Simply threading an oversize oil drain plug (with appropriate washer, of course) into you case may solve all your problems; worth a try, IMHO.
I'll post a link to show the vast array of oversize and repair oil drain plugs available:
Again, expect opposition from insert aficionados and others, but--in my experience, an oversize oil drain plug can work and seal indefinitely (don't overtorque THAT one, although both first and second oversizes are available).
Good luck; try it, you'll like it!