From Mechanical Database
The 5.4 3-valve engine found in Ford pickup trucks such as the F-150 has an irregular spark plug design which sometimes breaks during replacement, usually due to lack of regular maintenance at proper intervals. Because the spark plug body extends much further than the thread, there is an area for carbon, rust, and other things to build up. Over time the part of the spark plug becomes embedded in the cylinder head and is harder to remove than the weak spark plug design itself can tolerate, this results in the spark plug separating in two pieces and only half of the spark plug coming out during replacement.
While some may think this is the end and removal of the cylinder head is necessary, removal is actually not too hard with a special tool. Following is real world experience regarding the problem, along with a service bulletin from Ford regarding the issue.
The following was attempted after all other methods failed. The bulletin and several other sources on the net called for using tweezers to pull the ceramic center out, which is impossible. The ceramic is typically wedged in so tightly that even pliers would not pull it out, if there was even enough room to insert them.
Although a risky procedure, at one point running the engine was attempted as a last resort prior to purchasing the tool. Since the bottom half is tapered there is no way it can get sucked into the combustion chamber and create damage. The idea was that pressure from the compression cycle would push it out. This failed to remove the broken spark plug half, even after reaching operating procedure and doing over 3,000 rpms.
Prior to performing the following procedure, it helps to spray some penetrating lubricant into the spark plug hole and let the vehicle sit over night. Then the following morning everything should be removed by applying compressed air to the spark plug hole to ensure there is no dust or debris that can make it's way into the combustion chamber.
- Obtain a mirror or clear the viewing area to get a look down into the spark plug hole to see how much of the porcelain is still left in the bottom half of the spark plug, this is not required but helps grasp the overall situation.
- Insert the spark plug removal tool shown below into the spark plug hole, once the threads that would normally be the spark plug are completely tight, begin to tighten the second half. This is the part that will pus a rod into the porcelain to move it down and create access for the second part of the tool to thread into.
- As the tool begins to push the porcelain down, it will crack some of it's pieces. These should be blown out with an air hose to prevent their entrance into the combustion chamber after the plug's removal. During one instance, the tool compressed down on the electrode so hard that it got embedded in the fine point (probably designed specifically so) in the tool, and after the tool was removed for inspection of the progress the electrode came out with it.
- Continue to drive the tool until it is felt that it can go no further without excessive force. This happens when the electrode presses into the outer most part of the spark plug.
- Insert the second tool and begin to turn the inner part counter clockwise (direction depends on tool) so that it threads itself into the empty shell of the spark plug lower half.
- After several turns, begin to turn the outer part of the extractor tool so that it will pull and extract the spark plug lower half. If this fails, the inner part may have to be threaded in further.
Prior to reinstalling the plugs, follow the last recommendations in the following service bulletin. These issues can be avoided with common scheduled maintenance whether performed by self or an automotive mechanic. The previous experience occured to a neglected vehicle with original spark plugs at 96,000 miles!
Service bulletin TSB 06-5-9
Some 2004 F-150 vehicles with a 5.4L 3-valve engine may experience difficulty with spark plug removal which may cause damage to the spark plug and leave part of the spark plug in the cylinder head.
- Make sure the engine is warm (hand touch after cooling down).
- Remove the coil-on-plug assemblies and thoroughly blow out the spark plug wells and surrounding valve cover area with compressed air.
- Back out the spark plugs, no more than 1/8 to 1/4 of a turn. Apply penetrating oil (AeroKroil or equivalent) and fill the spark plug well just above where the jamb nut hex sits. A minimum period of 5 to 10 minutes of soak time is required. The penetrating oil will wick down to the ground electrode shield in this time.
- Slowly turn the spark plug out. Some screeching and high effort may be noticed but, not in every case. The expected removal torque is about 33 lb-ft (45 N-m) but should decrease on the way out. If it is higher, try turning the spark plug back in a half turn, then back out again. If the turning torque still seems high, repeat the back and forth rotation along with some penetrating oil to reduce turning effort.
If the plug does come apart even after following the General Spark Plug Removal Procedure, it will break in one of two modes:
- Mode 2
- The porcelain center and ground electrode shield is left behind and only the upper jamb nut comes out. In this case more soaking is required and long-reach nose pliers should be used to grasp and remove the porcelain center from the ground electrode shield.
- Once there is only an empty ground electrode shield left in the cylinder head, perform the following steps to remove the shield using Rotunda Special Service Tool 303-1203.
- This tool is only designed to work with an empty ground electrode shield. If the spark plug came apart in Mode 2, the porcelain center must be removed prior to following these steps.
- The combustion chamber must be protected from contamination during the extraction process by using a modified vacuum cap (382444-S) as a stopper-type plug. This is because the remaining ground electrode shield will be thread-tapped, so the cap is needed to prevent thread chips from falling into the cylinder bore. Cut a vacuum cap to a 3/8" (10 mm) length for each ground electrode shield that needs to be removed.
- Install the modified cap with a long drill bit or suitable wire, sized for the internal diameter of the cap. The rubber cap should bottom-out on the electrode strap of the ground electrode shield once installed.
- Thread-tap the ground electrode shield Using a 9.0 x 1.0 mm "plug" tap (tap profile is about 3-4 reduced diameter threads on the tip end).
- Coat the end of the tap with general purpose grease as shown.
- Turn the tap about 3 to 4 turns into the ground electrode shield once the tap begins to cut. As the shield is tapped, for every 1/2 turn, the tap should be backed up 1/8 turn to "break chips" and prevent any cut material from coiling-up and laying in the spark plug well. All of the thread chips will embed in the grease pack or drop inside the vacuum cap when following this procedure. A suitably sized tap wrench of about 7-9 inches in handle length will aid in reaching down the well. If not available, use an 8 point socket with a ratchet and drive extension. Keep the shank aligned with the axis of the spark plug bore cavity to prevent possible thread bore damage. Use care not to damage any spark plug threads on the way in.
- Carefully back out the tap while maintaining the residual grease coat on the tap which contains some chips. Take care not to touch the sides of the spark plug well bore during removal.
- Once the ground electrode shield is tapped, thread Rotunda Special Service Tool 303-1203 into the ground electrode shield to extract it from the spark plug well and encapsulate any remaining chips from falling into the combustion chamber.
- Install the stepped end of the tool pilot bushing into the spark plug well ensuring it bottoms out.
- Screw the center shank into the ground electrode shield. Do not over tighten the shank, to prevent thread stripping.
- Install the nylon washer and jack nut until finger tight.
- Turn the jack nut with a socket and 3/8" drive ratchet until the ground electrode is freed from the cavity and withdraw the tool assembly. Several turns of the nut are required. Upon removal, any remaining chips not caught earlier by the tap grease will be captured by the rubber plug sitting at the bottom of the ground electrode shield.
Once the spark plugs have all be removed, new plugs should be installed using a film coating of nickel anti-seize on the ground electrode shield of the new spark plug. Do not coat the electrode strap or the plug will misfire. The new plugs should be installed with no lubricant on the threads and torqued to specification, 25 LB-FT (34 N-m).