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Truck Trend Garage: 2004 Ford F-150 SuperCrew 4x4 Bag Plugs

Expert Advice

Alex Steele
Dec 6, 2011
Question: I bought a 2004 Ford F-150 SuperCrew 4x4, with the 5.4-liter 24-valve V-8 and about 90,000 miles on it, from my local Ford dealer. After the 95,000-mile service, the manager gave me a laundry list of Ford-suggested services for next time, including spark-plug replacement. Four weeks ago, I took it in for the 100,000-mile service. Long story short, a $940 one-day service stop turned into a $3690-plus bill and 22 days without my truck, because the mechanic managed to break six plugs and had neither the skills nor the proper tool to do the job right.
Here's the rub: Neither before nor at any time during this process did anyone at that establishment tell me this is a common failing with this engine, and that Ford has long since washed its hands of all responsibility. They just harped on the fact that spark plugs are not covered in any way by warranties or service contracts -- which I fully understood going in.
Photo 2/2   |   Truck Trend Garage Bad Plugs Z
I only learned of this long-standing defect because my youngest son has one friend in particular who specializes in racing and servicing Ford trucks (guess who will service my trucks here on out). Incidentally, before they finally finished my truck, they had two similar ones in their shop with the same problem, one with all eight plugs broken.
Answer: This defect is not a highlight for the Ford engineering team. It began with newly designed spark plugs installed in their three-valve engines for the 2004 model year. The new plugs consisted of a "ground electrode shield," which extended the end of the plug about 1.5 inches deeper into the cylinder head (past the threaded portion). Due to corrosion and carbon buildup, the shield becomes seized in the hole, oftentimes resulting in the plug breaking off during removal, and possible cylinder head damage. Your service department most certainly should have informed you of the risk and potential cost, given the worst-case scenario.
Ford's latest technical service bulletin dealing with the problem gives a long and detailed procedure to get the plugs out, and extract the remains if they break off. It starts by backing the plugs out no more than 1/8- to 1/4-turn, squirting Motorcraft Carburetor Tune-up Cleaner into the spark plug to penetrate the threads, and then patiently working the plug back and forth. If a plug breaks, depending on exactly how it broke, there's a lot more work to do with the use of designated special tools and extraction procedures. When the problem V-8s were covered under the manufacturer's powertrain warranty and spark-plug removal stripped the threads in the cylinder head, Ford would simply replace the head. But it has published a non-warranty procedure for cylinder-head repair, approving the use of the Lock-N-Stitch aluminum insert and tool kit. When replacing spark plugs, use the latest part number recommended by Ford or look to the aftermarket, and coat the ground electrode shield with Motorcraft high-temperature nickel anti-seize lubricant. According to Ford, this spark-plug dilemma involves three-valve 5.4- and 6.8-liter engines built before October 9, 2007, and 4.6-liter 3V engines built before November 30, 2007. There is no warranty extension, campaign, or special policy at this time.

Can't wait for help with a problem you're having with your Truck or SUV? Ask the expert we trust here at Truck Trend Garage -- visit Alex Steele at
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