I've been looking for an '05 and up Mustang GT as a DD replacement. I've heard of the plug breaking issues w/ Ford V8s but Googling the forums report a cylinder head and/ or plug redesign in '08 which 'should' remedy the issue depending on the engine build date. Posters say engine build dates anywhere from late '07 thru mid '08 would have the redesign, but I dunno.
Is the plug breaking issue really that bad on earlier ('05- '07) engines or is the redesign the answer? Some owners were pulling the plugs at 5-10K miles and coating w/ Nickel anti-seize JIC.
I haven't kept up w/ Ford stuff in a long time but I'm pretty set on the GT. I found an '08 GT w/ 23K miles that hits all the right buttons, is there anything else to beware of w/ these? I would plan on driving it for 5 years or more at around 12-15K/ year and really don't need any more headaches for the duration if at all possible.
TIA
Javelin
MegaDork
3/29/13 11:53 a.m.
All of the 05-10 Mustang GT's are a 3V head, which doesn't suffer the same plug blow-out issues as the previous 2V ones. Instead, the stupid OE Motorcraft plug gets stuck in the head and breaks in two. If the plugs have been replaced at all, you should be okay. BTW, the switchover happened in 2008: " 2008 Mustang GT models built prior to 11/30/07".
F-150s of that vintage have the same issue. There's a lot of material out on the web about how to deal with it, including special tools and a TSB from Ford. I bought the tool, followed the TSB, and changed the plugs in my 07 F-150 without too much difficulty.
In short, it's an issue, but not a deal-breaker.
There's a special tool you can get just for removing spark plugs. Several enterprising individuals on various Mustang forums have bought them and will rent them to you for cheap.
The Lisle tool is better than the Motorcraft one.
You can really reduce the likelyhood of breaking the plugs if you remove them with a 3/8 impact wrench. Really. No, I'm serious- it works.
Don't reinstall with the impact, please.
Thanks all for the info. I'll look at the '08 prolly Monday. It's at a Ford dealer so they prolly sold it new and serviced it as well. If it all checks out it could be mine. 
Streetwiseguy wrote:
The Lisle tool is better than the Motorcraft one.
You can really reduce the likelyhood of breaking the plugs if you remove them with a 3/8 impact wrench. Really. No, I'm serious- it works.
Don't reinstall with the impact, please.
I used the opposite approach. After soaking them overnight in the carb cleaner (per the TSB), I backed them out very slowly and gently. I only broke one. The Lisle tool is the one I have, and it worked great, once I figured it out.
I'm pretty sure I posted some pics on here when I did the job, but damned if I can remember what thread it was in. Something to do with F-150 Triton engines.
I did the plugs on my 05 GT at 89k miles. Broke half of them, but I think with some patience I could have done all of them without any breaks. The three I soaked with PB blaster and drove for a week, then hit with a 3/8 tq wrench spun right out. The ones I tried to do in the same weekend broke. The Lisle tool got them all, but on lost ceramic into the cylinder and required some shop vac cylinder clean out.
In short, it's not that big a deal. In NO way a deal breaker.
No, really. You will break fewer plugs with an impact than you will with the soaking routine. Really.
Old thread up.
I have a 05 GT 4.6. I'm getting a code for P0302 misfire in cylinder #2. So I pulled the coil and swapped it with another, and cleaned the MAF, and cleared the code. It came back. So I need to change the plug/s.
I'm reading all the horror stories, and figured I'd check GRM. Woila I found this thread. So is impact still the recommended way to get them out? And should the car be warm or cold if I go the impact method? And do you hit them with PB blaster prior to hitting them with the impact?
thanks
Try replacing the coil first. They usually need changed before the plugs. Or trying swapping it to a different cylinder.
octavious said:
Old thread up.
So I pulled the coil and swapped it with another, and cleaned the MAF, and cleared the code. It came back. So I need to change the plug/s.
Reading fail.
The last set I did on an Expedition. I got the engine warm, just cracked the plugs loose and spraying wd-40 in the plug wells and let it sit overnight. All the plugs came out fine the next day. Put anti-seize on the new plugs and torqued to 15 ft.lbs.
Multiple ways to do, just pick the one you feel most comfortable with. I personally wouldn't use an impact for fear of not being able to "feel" what was going on and stripping the head. If you're comfortable with it, give it a shot.
Many people have said it's also helpful to do seafoam beforehand. It cleans the carbon buildup off the end of the spark plug to prevent them from getting stuck.
3/8 impact wrench is the answer. Make sure someone has the Lisle tool available just in case.
3/8 impact is key, if the Lisle tool is there you won't break one on principal.
Had my expedition done by a shop. Dropped off several days early and they applied PB blaster and heat cycled 2x over the weekend leading up. None broke.
I saw the Lisle tool from between $70-130 and was curious if there was a rental option from your FLAPS.
I saw that Oreilly has a rental tool for Triton motors. But that's for the 3v F150 right, and not the Mustang right?
Apexcarver said:
Had my expedition done by a shop. Dropped off several days early and they applied PB blaster and heat cycled 2x over the weekend leading up. None broke.
I posted on the original, but if I had it to do over again, this would be my approach. Fill the plug wells with penetrating oil when hot. Let it cool overnight. Remove excess and drive it a couple days. Repeat. Then use a 3/8 impact while having the Lisle tool waiting on the bench.
Octavious - You are correct, the Triton was the 2V motor.
