1967_390

Hi, I am helping my son replace plugs and coils on his 2002 GT. One cylinder in particular was suspect to the engine running rough and making sounds. We pulled the plug and found the end was damaged and the threads were "smooth" and appeared polished. It looks like the plug unthreaded itself. The porcelain is also broken, but I don't believe any pieces fell into the cylinder, as it all came out together when we pulled the coil.

A new plug will not readily thread by hand. I don't know if the cylinder threads are deformed.

I have attached a couple pictures and am looking for information as to what I should do here. I have never seen something like this before.



Thanks for any info.

08'MustangDude

That damage is because the piston hit the plug, and that is your "sound."

pure_kaos

I actually had this happen to me not too long ago. Spark plug blew out the cylinder head taking the threads with it. The electrode was bent like that too. Fortunately there wasn't any piston damage. However, if I were you I would have the car towed to a shop and have it visually inspected. The threads for the spark plug are repairable. Most shops use a thing called a timesert. A few hours and done. It can be done by yourself, but requires a timesert kit, some research, time and patience. Good luck.

1967_390

This is the same information my mechanic provided, he has a mobile truck and will be coming this week to install the thread insert.

Thanks for the input.

Derf00

Blowing out of the plug from the head is actually pretty common on the 2V 4.6L

1967_390

So I have since read and discovered.
Thanks

08'MustangDude

Still, on order for the ground electrode to be impacted into the center electrode,
there had to be contact.