Spark Plug popped out.

[windydubber]

Last night, merrily driving along and had a loud pop and then more volume from the engine. Pulled over to see that
a Spark plug had popped out. I have mentioned the problem with this particular Spark plug on the forum before, but basically
when I went to change all four plugs this one was different. It had a smaller thread so I couldn't change it at the time.
I just put it back. Think it may have been helicoiled but not too sure.
Anyway I drove home about a mile on three cylinders as the only bl00dy tool I left out of the van from the weekend was my spark plug
spanner!!
I will pop the spark plug back in when I get home from work but my question is, long term, I guess this will just keep happening? So
what is the remedy? Am I looking at replacing the head? We are planning a big European trip in September so need to get it sorted asap really.
Cheers

[silverbullet]

You need a professional "Thread Doctor" to sort it.
If the plug pops out then there is no thread left in the head, so it needs an insert fitting.

[windydubber]

Could it have worked loose and popped out?

[silverbullet]

I think the "one plug was different" comment says it all tbh.

[windydubber]

So am I right in that it's probably been helicoiled? Sorry but I'm not a mechanic and learning as I go along.

[RCN]

Agree with Silver bullet.
I've seen Thread Dr at work and have to I was impressed. I'd try them 1st and then a new head if that failed

[windydubber]

Have you got a link to the thread doctor at all??

[windydubber]

Don't panic. If its the one in Hampshire I've found it!