Looking for a machinist who repairs cracked aluminum engine castings (engineering question)

[cstelluti]

What exactly is this plug used for? How frequently does it need to be removed?

it's a manufacturing plug in the casting. It's necessary so they can drill the oil galley behind it. Without that passage, no oil returns to the oil sump behind the transmission. Without that hole, there was no way to drill the passage.

 

[PGlaves]

The explanation on another forum is that it is only used for something in the manufacturing process, and users/mechanics aren't supposed to touch it. (Presumably because it's tapered and tightening it cracks stuff.)

I vote for a good clean-up, for a certified JB Welder.