Hi,

I was trying to remove spark plug which was able to lose on engine at temperature cca. 70C/160F, and I was able to made 5turns approx, and now it is stuck.

I put some penetrating spray, start engine, it was able to move 1/4 of turn, now it cant do back and forth movement.

So I heard that acethylene and Automatic Transmission fluid mix 50/50 is best for seized bolts but dont have it.

So what to do if i assume that aluminium matter or carbon at the beginning of spark plug forbids to remove it?

Does repair shop do this with thread insert without removing cylinder head? thanks

As per old-school, kerosene is one of the best penetrators.
But should give time to suck in threads.