Helicoil it before you don't have enough meat left to use. You might want to read up on the torque specs too.

 

mine squealed years and years before and after I rebuilt the engine.

Guess where the intermittant squeal came from? The air pump for the cat converter

 

Guess what!

My oil pressure guage returned. When it was not working, the oil level was less than 1/16" over the mark on the stick. I checked the oil level, when the guage returned, it was right on the mark. Crazy huh? Now Im about a 1/4 quart low, and its working fine. I must need a new sending unit