2001 GT stripped out spark plug hole in head

[Tnmustcobra]

I just spoke to a friend of mine and he said his 2001 GT "blew" a spark plug out of the aluminum head and stripped the threads in doing so. He said he heard from one of the sales counter person at NAPA that he has seen that problem before. I thought it strange for a plug to have been blown out thru the threads of the head. He said there are not that many threads on the end of the plug, so that might be one problem. Anyway, my friend said that NAPA has a kit to install a sleeve into the damaged plug hole and that this kit cost somewhere around $387. Not sure exactly what is in this kit other than at least one sleeve and a tool that you use to help run the sleeve into the head. The sleeve cuts into the head as you drive it in and you just remove the tool and install your new plug. Has anyone seen this problem and if so, any suggestions? I told him to try the local Ford dealer to see what they would charge. Might be a few dollars cheaper since they probably have the tool and kit, but not sure.

Has this happened to anyones Mustang Cobra?

Any comments or suggestions would be appreciated.

Thanks,
David Morrison

1997 Mustang Cobra
1987 Porsche 944 NA
2004 F-350 Dually
1988 Mustang AV8SS Unlimited Race car (sold)

[decco]

The only way that plug could have "blown out of the head" is if the plug was very loose to start with. Don't know about the NAPA repair, though.

[crutch95]

I had it happen on a 5.4 L truck. We had to have a repair kit put in it. I dont kow what the called it. But it has worked so far and has been in for about 8,000 miles. I will try and find out what they called it for sure. hope this will help.

[cfradam]

there called heli-coils. http://www.emhart.com/products/helic...FQgfswode2s8kQlike what was said above the 2003 and older 5.4's only came with 4 threads in the cylinder head.if not torqued properly or if to much boost was used the plug will just blow out taking the threads with it.you can get these heli-coils from any auto parts store

[Tnmustcobra]

I looked up heli-coils and also spark plug hole repair kits and found a threaded insert repair kit from Time-sert that was specifically designed for the Ford engines. The heli-coil kit is cheaper in cost and I have used them on engines before...just not in the spark plug hole. The guy at NAPA had the kit and it was made by Heli-Coil, but evidently it is not a heli-coil but a threaded insert. I think it would be similar to the Time-Sert threaded insert that they make specifically for the Ford engine. When I went to Time-Sert website, they had a section with the latest news and asked" have you had a 5.4L spark plug blow out" ? This evidently can happen and is probably due to the short thread length on the plugs and if torqued too much, I could see damaging the threads.

So, is a heli-coil sufficient to hold a spark plug in while being subjected to compression strokes?

What did it cost to have the inserts installed in your 5.4L truck and did you find out what they were called? Did you take it to a shop for repair or do it yourself?

Thanks for everyones help. My friend is trying to decide if he wants to tackle this project himself or take it to a repair shop or dealer for the repair.

Thanks,
David Morrison

1997 Mustang Cobra
1987 Porsche 944 NA
2004 F-350 Dually
1988 Mustang AV8SS Unlimited Race car(sold)