that's a steel thread repair insert.

remove it from the spark plug that it came out with ..( or get a new
insert )

put anti-seize compound on the threads of the new spark plug ( as all spark
plug threads  must have )

screw the new plug into the insert.
and use the new spark plug as an installation tool

I would put lock tite on the outside threads of the insert to hopefully
stick it permanently into the head.

I'd tighten that spark plug properly, but I wouldn't overtighten it for sure
..
or the insert might just come out with the spark plug next time.

scott
tuirbovans
hoping this only posts once
----- Original Message -----
From: "Harry Hoffman" <hhoffman@IP-SOLUTIONS.NET>
To: <vanagon@GERRY.VANAGON.COM>
Sent: Tuesday, November 02, 2010 1:52 PM
Subject: spark plug threads

> Hi All,
>
> So, I started to tune up my vanagon but replacing the spark plugs. I
> took the second plug out and out with the plug came the steel (?) thread
> that lined the spark plug hole.
>
> I can still see threads in the hole but now the plug just drops in the
> hole.
>
> What are my options? Pulling the head and getting it re-threaded?
>
> Cheers,
> Harry