I had a local shop replace my spark plugs in my 2007 F150 because I didn't want to risk breaking the plugs and having to buy the extraction tool. Fast forward a few months and I start having a misfire on the highway (300 miles from home) and had to pull off to get it looked at. The shop looked at the offending cylinder's plug and the electrode was gone (hence the misfire). So they replaced that plug (and I had them replace the others as well) for a nominal astronomical fee.
My question is does Motorcraft stand behind their 2 year warranty pretty well since I had a shop do the work? If so, how do you get the ball rolling to get Motorcraft to pay up?

 

I'm waiting for you to let us know.

 

I'd ask Ford Brand Protection if they'll look at the plugs to determine if counterfeit.

 

My personal opinion is IF these plugs can be proved to be authentic Motorcraft product and the shop receipt shows their part numbers etc Ford would indeed stand by them. I do find it "interesting" the Ford or Motorcraft logos aren't shown on these plugs.

By all means keep us informed of your findings.

 

But if you look at some of the threads they show signs of blowby. plugs not properly torqued in are loose and allow combustion gases to flow up plug and suck air during intake stroke creating a torch affect . Just like a cutting torch it will destroy the plug .
Were these supposed to be sp546 the latest plug version not the dreaded sp515.s .
You very likely got counterfeit plugs/ But they must be torqued to 25 foot pounds not by feel . . I still use a tiny bit of nickel anti seize on threads and barrel . Nickel is good for 2400 deg F , you can get it on amazon .
it is good to clean carbon out of spark plug hole with carb cleaner. No fuel additive can get to that 1 inch snout hole. Carb cleaner dissolves carbon . Carbon can break plugs going in and changes heat range of plug , get it back to factory clearance.
Do your own plugs correctly ,your labor is free no one will do it as good as you if you study it . Put new boots in . Change plugs every 60k . Shops take every shortcut they can to make money .

 

I bought a set of SP-515s to replace the OEM SP-507s in mine, but before doing so, bought some newer SP-546s at greater cost. Considering costs, I think the SP-515s are maybe not legit and something about the printing? I bought the Lisle kit in two stages, as I ended the first day with 7 changed, and #8 stuck out of reach after only the threaded body came out ... I could not get to the porcelain with center electrode. Overnighted the extra 65710 part, it got it done in a few minutes. I have a Mustang with 4.6-3v too so the tool set does have value for me ... even after doing the truck. Otherwise, I only had 2 out of the 8 not come out good. I dosed with Kroil before starting, used the nickel A-S on my threads and barrel only,

Was in 2019, and was still good as of yesterday after about 11,xxx miles.



I did like the way the SP-507 & SP-515 lower barrel was made one piece. SP-546s have a welded ground strap or stirrup.

 

Anything mentioned about where that electrode is now?....

To me that's THE issue here.

 

Probably in a cat.

 

Those sp515's were horrible ' you can tell them by the blue weld . That process often broke the porcelain inside, many times they were bad right out of the box .
I must confess after the original broken plugs I got out I went to champion 7989. Still using them , they proved to me they would not break .
I have a box of sp515's but I'll never use them . I have tried some sp546,s in an emergency but its a pain dealing with a different size socket as champs are 5/8 - sp's are 9/16.
That electrode may have went out the exhaust or is imbedded in piston . As long as the compression is good I would not worry .

 

Yeah, I noted the blue weld on the SP-515s too, and the tapered seat on the SP-546s looked better too. I also noted that the SP-546s have a longer exposed porcelain raising the spring seat and it looks like it would put a more positive squeeze on the coil spring above, like for better contact maybe. Someone once told me the SP-546 lower barrel was smaller in diameter, but I found mine were all the same. I too likely will not use these SP-515s, and I have a dedicated socket with ball jointed end and a strong magnet.