hmmm, well, I went to the mech. to get the spark plug hole fixed. He mentioned something about a heli-coil. What is that? Is that a tool to fix the thread or is it a device (or piece) that actually goes into the sparkplug socket and acts as a new thread. Anyway, he said the damaged thread was very minimal and that he didn't have to use any separate piece to put into the sparkplug socket. I think he said that he just rethreaded the socket? I dunno. But the car is fine and everything. Now, my concern is the metal that came off the damaged thread and any grime that came off too and fell into the sparkplug hole. Where do they go if they fall in? Should I be concerned? The mech said I shouldn't worry about it. BTW, hewas a Volvo mech. I have heard different stories. Some people said it could mix with the oil and damage the cylinder heads, others said it will shoot out the exhaust. Funny how I had a quote of over $2000 for a new head because of a damaged thread. Anyhow, all is well. The mech said there is nothing to worry about and that the plug won't shoot out. I can drive it the way I have been driving it before. Is there anything to be concerned about? The metal shavings from the thread falling into the socket kind of concerns me. What have your experienve been like? Thanks guys for all your help!!!!!