04Blue281

Have been enjoying my recently aqcuired 2004 Mustang GT --- up until today! I bought this car a few weeks ago (approximately 134,000 miles on it) --- figured I'd better change the spark plugs (not having any idea how long they'd been in there).

Started at the right front (Cylinder #1). Everything going fine until I got to Cylinder #3. The plug in #3 wasn't tight --- didn't need to be "broken loose", just spun right out. The spark plug looked pretty nasty compared to the other two I'd already removed, with black crap on the ceramic body of the plug (which I assume must be blow-by from the cylinder). Not wanting to acknowledge what I already feared, I applied anti-seize to a fresh new plug and attempted installation. Not happening --- no threads to accept the new plug. Aaahhhrrrrgggg!!! [I didn't actually say Aaahhhrrrgggg --- I said some really profane stuff.]

Went on and did the rest of the spark plugs --- no problems. All "broke loose" with a feel I expected and all them felt right when I torqued them at 160 inch-pounds.

So, the damage is done --- just have to fix it. My first thoughts were that the cylinder head will HAVE to be removed to fix this. But, maybe there are other workable options?? This is a fairly common occurance on these heads?? What do you suggest??

Sonic Mustang

Ford authorized a Lock N Stitch repair kit for damaged spark plug threads on out of warranty modular engines.

Call these guys to make sure you buy the right kit. They have the TSB approving Lock N Stitch on the web page.
http://fulltorque.com/sparkplug.htm

04Blue281

Thanks for the info. Much appreciated!

ZeroTX

Sounds like someone knew about this and patched it up enough to sell it to you. No idea how it didn't fly out. I'll bet they were praying it wouldn't blow out on the test drive.

The method above is what people usually say to do. It sucks to have to do it. I am putting a 2009 4.6L 2v (Crown Vic) motor in mine and I'm hopeful that maybe the 2009's have more threads on the heads.

Sonic Mustang

The only thing I know for sure is '04 4V heads have more threads than '03 4v heads.

Take a look at the link I provided. There are Lock N Stitch thread kits for all kinds of Ford heads. They come in different diameters and lengths suggesting some 2V heads have more threads than others. Maybe the company can tell you if your '09 heads have more threads than earlier versions.

Then again, you can just take a plug out of your replacement engine and count how many turns it takes to seat it.

04Blue281

Well.... maybe, but I thoughourly inspected all 8 of the removed plugs --- they all looked liked they'd been in there long enough to be due (over due?) for replacement. No indication of any problem other than cylinder #3 --- just old plugs that were ready for replacement.

But, whatever might have been done previous to me owning the car doesn't really matter. It's my problem now --- just have to fix it and move on.

fordfreak_24

same thing happened to me and I used a kit that napa sold. cost about 80bucks and I have yet to blow it out.

04Blue281

Problem is fixed. I wrestled with the idea of fixing it myself or letting a local Ford dealer fix it. I decided to let the dealer do it for two reasons ---

1) I had never done this exact repair before.

2) If something DOES go wrong with the repair, I'll be hitting them up to make it right.

I've been running this thing prettty hard since the repair has been done. Many, many pulls in gears 1 and 2 to 6300-6400 rpm. And quite a few in gears 3 and 4 to 6100-6200 rpm. [My engine rev limiter is set at 6400 rpm.]

I'm happy that the problem is fixed ---- and I truly appreciate the input that I got from people on this forum.