Watch Out for Ford Motorcraft Two-piece 16mm "High Thread" Spark Plugs That Break!
The original equipment Motorcraft brand spark plugs that were factory installed in many late model (2004 to 2008) Ford trucks with 5.4L V8 and 6.8L V10 engines, 2005 to 2007 Mustang GT 4.6 & 5.4L V8 engines, and 2008 Mustang GT models built prior to 11/30/07) can break when you attempt to remove them!
Vehicles with these spark plugs include:
2004 - 2008 Ford F150
2005 - 2008 Ford Expedition and F-Super Duty
2005 - 2007 (and 2008 models built to 11/30/07) Ford Mustang GT with 4.6L V8 engine (uses 3L3E ignition coils)
2005 - 2008 Lincoln Navigator
2006 - 2008 Ford Explorer
2006 - 2008 Lincoln Mark LT
2006 - 2008 Mercury Mountaneer
2007 - 2008 Ford Explorer Sport Trac
F-53 Motorhome chassis
The Motorcraft PZT 2FE Platinum spark plugs have a crimped lower electrode shell that becomes coated with carbon, causing it to stick in the cylinder head. Rust and corrosion on the lower plug shell can also cause it to stick. When you attempt to unscrew the plug, the lower shell breaks off and stays in the head. Removing the broken shell requires a special Ford, Snap-On or Lisle extractor tool. Worse yet, if any shell or electrode fragments fall into the cylinder and can't be fished out, you may have to remove the cylinder head to get the debris out.
Many experts recommend replacing the original equipment Motorcraft spark plugs before the get too many miles on them (over 40,000 miles). Replacing the plugs at low mileage will reduce the risk of them sticking and breaking. Waiting until the original equipment spark plugs have 100,000 miles on them is asking for trouble!
If your vehicle has a lot of miles on it (say over 80,000), and the spark plugs have never been replaced, it might be best to just leave them alone. The original equipment Motorcraft spark plugs have a platinum tipped center electrode. The plugs should last upwards of 100,000 miles or more. Many plugs will actually go up to 140,000 miles or more with no problems - provided the engine is not burning oil and sees enough highway driving to keep the plugs clean (frequent short trip stop-and-go driving can cause plugs to foul). So as long as your engine is starting and running fine, and getting normal fuel economy (no misfiring and no Check Engine light with misfire codes), there is really no need to replace the spark plugs.
Here's another thought. If you are planning on selling or trading your Ford truck or Mustang within the next couple of years (and it is running fine now), leave the spark plugs alone and let the next owner worry about changing them. The risk is if you attempt to change high mileage plugs and break off several plugs (which commonly happens), those spark plugs could cost you a lot of money. Many Ford dealerships are charging $600 to several thousand dollars to change the spark plugs on the 5.4L, 4.6L and 6.8L engines that have the two-piece Motorcraft spark plugs. Why? Because the plugs usually stick and break, and it takes a lot of time and effort to extract the debris from the spark plug holes. In some cases, it may even be necessary to remove the cylinder heads to complete their repair.
If you want to read a long list of horror stories from Ford owners who have had to deal with the broken spark plug problem, Click Here.
Ford Technical Service Bulletin 08-7-6 covers the recommended removal procedure for these spark plugs, as well as the repair procedure if one or more plugs break ( Click Here to View Ford TSB 08-7-6). NOTE: TSB 08-7-6 supersedes the earlier TSB 06-5-9 that also covered the same subject. The difference is that the newest TSB says to remove the spark plugs when the engine is COLD (at room temperature). The older TSB said to remove the spark plugs when the engine was WARM (not COLD and not HOT). They theory was that a warm engine creates a little more clearance between the plug shell and cylinder head. But removing spark plugs on a warm engine with aluminum cylinder heads also increases the risk of damaging the threads in the spark plug hole, too.
First, make sure the engine is at room temperature (COLD).
Loosen each spark plug about 1/8 to 1/4 turn. Then Stop!
Spray some WD-40 or penetrating oil into each spark plug well. Allow the oil to soak into the threads so it can loosen any carbon or corrosion around the electrode shell. Wait at least 15 minutes, or longer (overnight is recommended if the plugs have over 80,000 miles on them).
After the penetrating oil has had time to work, slowly loosen each spark plug, applying no more than 35 ft. lbs of torque to your wrench. If a plug sticks, retighten it half a turn, apply more penetrating oil, wait, then try again. The plugs may squeal and groan, but will hopefully come out without breaking.
Removing carbon from inside the combustion chamber prior to changing the spark plugs can also reduce the risk of the spark plugs sticking and breaking. Using Top Tier gasoline or adding a fuel system cleaner (such as Chevron Techron or equivalent) to your fuel tank regularly can help reduce carbon buildup inside the combustion chamber. If you engine has a lot of miles on it, and/or is using oil, using a Top Cleaner treatment to remove carbon prior to changing the spark plugs is highly recommended.
If You Break a Spark Plug
If you break a spark plug, see the Ford TSB 08-7-6 to see Ford's method for removing the broken electrode shell from the cylinder head.
Here is a short video on how to use NAPA Ford Spark Plug Extractor SER 4663.
Lisle Tool also sells a spark plug repair tool for these applications (part number 65600). For details about this tool, Click Here. To see the instructions on how to use the Lisle tool to remove a broken spark plug insulator shell, Click Here.The Lisle Tool is available online at Amazon and from Snap-On tool distributors.
Do NOT reinstall the same Motorcraft spark plugs (PZT 2FE Platinum). Replace the original equipment spark plugs with one-piece spark plugs from Champion Spark Plugs(part number 7989), or similar spark plugs from NGK, Denso or Bosch. Several aftermarket performance companies (including Roush) also sell a stronger one-piece replacement spark plug for these engines that won't break. Note: the Champion spark plugs require a larger 5/8-inch socket to install (the original Motorcraft plugs have a 9/16-inch hex shell).
Apply nickel anti-seize to the outer surface of the lower electrode shell (the smooth part) before installing the plugs.
Tighten the new spark plugs to 25 ft. lbs (34 Nm).
Replacing the rubber boot that fits between the coil and spark plug is also recommended to prevent arcing that can cause misfires.