Some how I stripped the treads when installing one of my rear oil pan bolts. What's the better option, helicoil, or tap/die? Can this be done without removing the oil pan (again)?

 

personally, i would tap it to the next size.
but if you want the same size,then Helicoil is the answer

 

Helicoils are a very good repair, and easy to install. It is a professional repair and will allow you to keep using all the proper matching bolts instead of needing several different wrenches to remove the pan and having to keep track of which bolt/screw/staple goes in which hole.

 

torquefan has excellent points but hopefully you'll never have to touch the pan bolts again.
I would tap it to the next size.

 

Thanks for the advice guys. And yes I hope this is it for the pan gasket. That wasn't much fun.