The Ford Three-Valve Broken Spark Plug Blues - Four Wheeler Magazine
If you are the owner of a Ford truck with a three-valve (3V) modular V-8 or V-10 engine built from 2004 thru 2007, you have either faced the misery of broken spark plugs-or you will. The Ford 4. 6L, 5. 4L or 6. 8L 3V engines are some of the best and most durable engines Ford has ever built, but like Superman, they have a Kryptonite weak link. In this case, it's the OE Motorcraft spark plugs. They don't typically fail in service but often break upon replacement, leaving a piece in the cylinder head that can lead to an expensive repair. " Here is most of what you need to deal with broken spark plugs in your 3V Ford Modular. Our informal survey of the costs of having it done at a dealer or independent repair shop range from $600 to $1,200, with only a few broken plugs. If parts fall into the cylinder and the head must be removed (which necessitates lifting the cab), the cost can run $2,000 to $3,000. The High-Thread (HT) Motorcraft plugs for the three-valves built through 2007 (built by Autolite and also sold... It's almost a guarantee that at least one spark plug will break. Early on, Ford developed a special removal tool and came out with a Technical Service Bulletin (TSB) with detailed service procedures. Source: www.fourwheeler.com
