Spark plug thread gone :/

[JimmyT25]

Today I decided to replace my spark plugs, upon replacing them I noticed one was a bit wobbly so I was careful when I did it up as I think at some point someone has cross threaded it and stripped some of the tread out.
I tried to start the van and a hissing noise was made when turning it over, I checked the plugs, removed and re tightened the dodgy one and the last of the remaining thread came out of the head

I'm now wondering whether to use a helicoil or time time sert to try and sort it? I'm also assuming these are options that can be done with the engine in situ? If anyone could advise on which option is best, what I need and how to do it that would be great. I have re tapped threads etc before but I haven't used either helicoil or time sert before.

James

[bigherb]

I generally prefer inserts for spark plug repairs it has been known for helicoils to wind into the combustion chamber when replacing spark plugs.