I pretty much took in all the advice you guys gave me (and from elsewhere too) and went ahead with the procedure with the oil pan still on the car.
One big difference though: Instead of using a tap, I used my oversize plug... I was stubborn and did not want to buy the tap nor take the pan off the car.
Here's how I did it:
- Jack the car up; stands.
- Drained the oil.
- I used an oversize "self-tapping" plug, put a glob of heavier grease all over the threads (i used silicone-based) and started tapping it into my oil pan with a smaller ratchet.
- I ratcheted twice (~<=1/4 turn each) and backed out once.
- Repeat #4 until I felt some pressure increase and then I took the plug out all the way, cleaned all the shavings off, re-grease the threads, and started ratcheting again (#4).
- Once I got past the middle, at some point I started to feel a lot of pressure, and was forced to switch to my breaker bar. Repeat #5 with breaker bar.
- Got to where the rubber gasket touched the oil pan, took out the plug and cleaned it.
- Re-greased and threaded the plug in, took it out, and cleaned it. Repeat a few times until the amount of shavings between the threads on the plug are minute. It became significantly easier to put the plug in now.
- Poured 1-2 quarts of oil in the top and took the oil plug out from the bottom.
- Let engine drain, clean plug, clean inside of the threads of the oil pan (i used a small towel and jammed a small part of it in and threaded it out. got a good amount of shavings out).
- Repeat from #9 until the inside of the oil pan threads and the threads on the plug are clean. (it would not completely stop having some amount of shavings between the threads when I took the plug out. I'm pretty sure its still grinding a little and generates some shavings as it moves in and out. It's a rather small amount of shavings and they are all stuck in between the threads (and my grease) in the middle of the threads so I feel like its okay... it was late and i got tired so I decided to stop after 1 repeat.)
- Put the plug in and fill car with oil, check for leaks.
- Start car and check for leaks.
- Drive around a bit and came back and checked for leaks.
- Seemed good for now (i also have a crank seal leak still)
This whole process took a very long time. Steps 1-7 took me 40+ minutes. I took it very slow and did it very carefully. Particularly careful with the breaker bar.
After about a month? or less possibly? I changed the oil again for good measure.
Collected the oil and sent it in for UOA.
Came back relatively good. Slightly higher than baseline for iron but they didnt mention it at all in the notes. Slightly high in chrome, which they did mention, but said just keep an eye on it, its probably fine. I will see on my next UOA.
I did this sometime from mid-February to early March. It is now early June. Still running well (or at least the same as before this operation).
I would suggest others to get a threaded tap like the ones mentioned in the other answer/comments and use the right size plug for the tap. This would minimize or completely get rid of the small amount of shavings I get between the threads every time I thread the plug in.
Or take the oil pan off and do it properly.