On 8/1/2018 11:44 PM, Arlen Holder wrote:
On 1 Aug 2018 23:30:57 GMT, Steve W. wrote:

Same threads as a spark plug. The easy repair is a plug rethread kit. It
has an oversized insert with a self guiding fluted cutter/tap
combination. Then you trim the threads on an insert so they don't block
the sensor tip. Screw it into place and screw in the sensor. About the
third time you drive the car that insert will become a permanent part of
the manifold.

Very common repair, done all the time.

Thanks for confirming it's the same threads as a spark plug, which, at the
moment, seem to be 18x1.5 for them.

Googling, it seems cast iron isn't easy to weld, and that the plug rethread
might work, but, the heat cycling has likely hardened the bung nut, such
that it's a LOT harder (some say) to deal with than a spark plug thread
which is typically in aluminum engine blocks (they say).

Searching for this "plug rethread kit", is this the $62 kit you speak of?
https://www.amazon.com/Thread-Kits-1.../dp/B0025PQITU


That looks just like a helicoil set.