F150 spark plugs
 

Just a word of warning , if you own a F150 with a 3 valve 5.4 engine 2004-2009 the sparks plug will break and leave a portion of the spark plug stuck in the head! Not to worry there is a procedure that you can use that limits the chance of one breaking if you are very patient. There is a TSB (TSB 06-15-2) out that explains the procedure in detail. If you do break one or all of them there is a tool available from Napa (Broken Spark Plug Remover for Ford 3 valve part # 77-4021) that is much better than the tool listed in the TSP. There are a few things that contribute to the spark plugs breaking. First they are a two piece design. Second ford recommends changing them at 100k mile. Third they where installed without anti seize. The plugs are rather unique and expensive, they have a ground electrode shield which extends below the threads, this is the part of the plug that gets stuck in the head. Carbon builds up between the ground electrode shield and the head. When you try to remove them they break before the carbon does. To avoid them breaking you must follow the TSP procedure and use penetrating oil to break down the carbon build up very slowly. I used PB blaster. If you do break some go buy the tool from Napa ($94) and follow the directions in the kit. The tool described in the TSP doesn't work as well and is hard to get if not impossible. For replacement I found 3 different plugs: 1-Auto Light HT-15 $11. 2-Motorcraft $16 3-Champion $29. The Autolight and Motorcraft are two piece design while the Champion is a one piece that shouldn't break. Hope this helps someone if you have any questions don't hesitate.

My Explorer has a 4.6L aluminum engine. I had the plugs changed at about 60,000 miles to avoid possible difficulties later on. Carbon buildup on threads that extend into the combustion chamber can also very easily screw up the threads in any aluminum heads.

Wayne

What if when you got a new one the first thing you did was remove the plugs and put anti seize on them? Would that make it less likely for them to stick and break when you try to remove them?

Ron

Ron,
Yes the lack of anti sieze is the main reason for them breaking, followed closely by how long the suggested interval to change them.

Wayne,

The threads don't extend into the combustion chamber. Fowled or siezed threads is not the issue and is commonly suggested as the problem. The penetrating oil is used to break down the carbon build up on the ground electrode shield not to free the threads. You must first just turn the spark plug 1/8 of a turn open very slowly this will allow the penetrating oil to whick down the threads and end up breaking down the carbon below the threads on the electrode shield...If you look at the TSP it show this in detail...Mac

Why isn't this showig up in the Active Threads? I', sure its something that I did wrong.

I`m "lucky" as I have the 2003 F150 / 5.4 two valve truck . If you visit the F150 Forum and use their search tab for spark plug blowing out or something similar ... pull up a chair , get some coffee and start reading . As MacVABCH said , this is a major problem with the three valve engine ... and at its worst will actually blow the plug out of the head . There are also some pretty good links on that site on how and what to do to fix any problems you run into . Looks like Ford didn`t have a better idea here .
I plan on changing my plugs this spring at about 50 k miles ... but there can also be problems with the Aluminum heads and the plugs on the two valve engine .
Sorry you had the problem , but you aren`t alone on this .

Bob

So is this the 5.4 only or the 4.6 as well?

Yes,

On all 3-valve Mod Motors

Looks like I am going to go ahead and change mine now at 24K miles then so I can hopefully avoid this.