If replacing spark plug was a video game, this is the boss that appears before you.
Some cars spark plug replacement can be difficult, but on the Ford 5.4L 3V this is considered the boss of all spark plug removal. These spark plugs are in Ford and Lincoln vehicles with V8 5.4 liters and 3 valve made between 2004 to 2008. Whenever I browse forums owners always brag about how they successfully remove all 8 spark plugs without any issue. Some owners joke around about how removing all 8 spark plugs without an incident unheard of. When I researched about this spark plug issue, owners mentioned car repair shops charge up to $1,000 to replace the spark plugs just in case there’s any issues. So this spark plug issue sparked my interest.
What is the issue?
The main issue is the spark plug itself.
Here is what the spark plug looks like all intact and at its happiest.
The spark plug is composed of multiple pieces. So if you’re really unlucky multiple of these pieces can get detached and stuck in the cylinder head.
After doing research about the issue. I noticed that owners usually get the lower shell and insulator tip stuck in the cylinder head.
What’s the causes this?
The breakage happens when the lower shell develops carbon build up. It’ll seize the lower shell against the cylinder head.
Here’s what the spark plug looks like in a cylinder head.
Here’s a zoomed in picture of what it looks like close up. There’s a really small gap between the lower shell and cylinder head.
The recommended spark plug change interval is 100,000 miles so this gives it enough time to develop carbon build up in the gaps. The carbon build up will seize the lower shell against the cylinder head causing the breakage when attempting to remove the spark plug.
Reducing any catastrophe
Overtime people have developed methods to prevent any breakage. What’s interesting is that Ford recommends that you do not remove plugs from a hot or warm engine and use any power tools. But surprisingly owners have been having a high level of success removing the spark plugs when the engine is warm and with power tools. While these methods aren’t guaranteed 100% success, these have been used by others that have helped them.
1. Before taking off the spark plug, try adding additives in the fuel to help break and weaken up the carbon buildup. Such as Sea Foam, Chevron Fuel System Cleaner, Royal Purple Max-Clean Fuel System Cleaner. If you want to be extra safe, you can cycle through two gas tanks with additives before changing your spark plugs.
2. Using penetrating oil. Some owners have mentioned that hey use a penetrating oil such as WD-40, B’aster, or Liquid Wrench to help loosen the break up. They would spray some penetrating onto the plugs and then let it sit overnight.
3. Using an impact air tool to remove the spark plugs. The torque from the impact tool is suppose to help break up the grips of death from the carbon deposits. Some owners have claimed a high level success when removing the spark plugs.
5. Lastly, remove the spark plugs when the engine is warm.
What happens if parts of the spark plug gets stuck?
Since this is a known issue lots of companies have made tools to help remove the broken spark plugs.
How to prevent this happening again?
If you do opt to use the OEM spark plug then you can use nickel anti-seize on the lower shell to help with any future seize.