Topic: 4.6L V8 3V spark plug problems

[Deuce]

Dropped by the local Ford agency today, to inquire about servicing the failed Shaker 500 CD changer in my 2008 Mustang GT signature car.  This is the second unit that has stopped working.  I can post a separate topic about this saga.

While at the dealer service counter and since the car is due for a spark plug change, I asked the Service Advisor if later-issue Motorcraft spark plugs were less prone to breaking off in the cylinder head than the original assembly-line plugs. The Service Advisor's comment, which I had not heard before, was that 4.6L 3V Mustangs are much less affected by this problem than other Fords which used the 3V motor, such as F-150 trucks.

News to me.  I hope he's correct and he can accurately speak through his long-time experience in the shop.

[AU SNK]

When I had my 05 GT with the 4.6 3V, I changed the plugs at like 50k miles and broke 4 of the plugs off.

[67gta289]

IIRC in 2008 there was a mid-year change to a new style that was not prone to breaking.  Unfortunately mine was a September build and I had to deal with the snap, crackle, and pop situation.

[AU SNK]

IIRC in 2008 there was a mid-year change to a new style that was not prone to breaking.  Unfortunately mine was a September build and I had to deal with the snap, crackle, and pop situation.

a spark plug breaking is one of the worst sounds I have ever heard on car LOL

[Deuce]

IIRC in 2008 there was a mid-year change to a new style that was not prone to breaking.  Unfortunately mine was a September build and I had to deal with the snap, crackle, and pop situation.

Same here.  The changeover to new style plug occurred just after my engine was built on October 11 2007, so I have the early design.  The plugs were changed ten years ago at 90K miles.  Dealer-installed replacement plugs were Motorcraft PZH1F (assembly line originals were PZT1F). 

Wondering aloud if the replacement PZH1F plugs are less prone to breakage (?).  The car isn't driven as much now - less than 60K miles in ten years.   But likely it's due time for another spark plug service.

[67gtasanjose]

Maybe I'm late to the game with my '05 GT but at about 32k right now and original plugs.
I own the tool for extracting the broken parts but haven't needed to use it for about 8 years or so.

[KevinK]

I changed the plugs on my 02 F150 5.4 motor at about 90,000 with no issues. Probably on a warm engine.

[67gtasanjose]

I changed the plugs on my 02 F150 5.4 motor at about 90,000 with no issues. Probably on a warm engine.

*that's not a 3-valve engine, there weren't ever issues with those.

[KevinK]

Sorry, I was told by several mechanics and several web boards these had the problem of broken spark plugs.

Correction:
The TSB states the 5.4 was included.
SPARK PLUG REMOVAL INSTRUCTIONS?4.6L Concern
3V/5.4L 3V/6.8L 3V Tracking#
069-2008-1155
FORD: LINCOLN:
2005-2008 Mustang 2005-2008 Navigator
2004-2008 F-150 2006-2008 Mark LT
2005 Excursion MERCURY:
2005-2008 Expedition, F-Super Duty
2006-2008 Mountaineer
2006-2008 Explorer,
F-53 Motorhome Chassis
2007-2008 Explorer Sport Trac
This article supersedes TSB 08-1-9