Cracking the Ford 3 Valve Spark Plug Problem

Between 2004 and 2008 Ford V8
(and some of the V10) engines had a unique type of
spark plug installed in them.  These plugs are quite
different from the standard plugs most everyone is
familiar with.  The first thing you notice is the threads
do not go all the way to the bottom of the plug and
the ground electrode is not the usually “J” shaped
electrode.  These are commonly referred to as
“High Thread Sparkplugs” They were specifically
designed for the smaller combustion chamber footprint
used in these engines.  This allowed the engineers to
be a bit more flexible with the head design.

You can find these plugs on the 4.6 and 5.4 V8 24 valve Ford engines. As with most modern engines the replacement intervals for spark plug replacement has gone from 60,000 miles to over 100,000 miles.  Of course in most cases these mileages far exceed any OEM warranty.  Removing these plugs after they have been in there that long does prevent a problem.  Especially with this design feature which allows carbon to collect on the lower section of the plug which is protruding into the combustion chamber.  It’s this carbon build up that makes it tougher than other plugs to remove.

There are a lot of different methods for removing these plugs and a lot of various special tools to remove the broken bottom sections if you do accidentally break one off.  This article covers the OEM approved method and the method that what was developed in the field by mechanics that actually get the job done.  Here are both methods for you to choose from and see which one will work better for you.

OEM Approved Method
   Engine should be cold, preferably 8 hours or more.
Remove the necessary covers and the individual coils.
Use a blow gun to remove any debris that is down in the plug area.
With a breaker bar or ratchet turn the spark plug no more than
an 1/8 turn.  DO NOT USE AN IMPACT!

Spray carbon dissolver into the plug area.  No more than a ½ to ¾ teaspoon.  Should be about the top of the hex nut part of the plug.
Leave it to soak for at least an hour before attempting to turn the plug.  If needed overnight is recommended.  Do not soak more than twice.  If you do, then after the plugs are all removed spin the engine over to blow out any of the carbon dissolver to avoid engine damage.
Use no more than 33 ft. lbs. of force in either direction while slowly turning the spark plug.  You may have to turn one way and then the other to loosen the carbon.
Always use an anti-seize when reinstalling the new plugs.
That’s about the longest procedure I’ve ever seen to remove 8 spark plugs.  Let’s move on to another method.

The None Approved Method
   Warm the engine up completely, and before it cools down too much remove the necessary items and coils.  (If you like… do one side at a time.  Just finish one side… put it back together…warm it back up… then do the other side.)  Once the plug area is blown clean you have two options at this point. 

Option 1 – Get your small impact out and go at.  (My preferred method)

Option 2 - Crack the plugs about an 1/8 of a turn and soak them down with as much of that carbon dissolver you feel is necessary. (Screw measuring, what little that is going to go into the combustion chamber can be spun out once the plugs are removed.  Although a lot of the dissolver just goes up in fumes even before you get started.)
Now back to the impact gun.
(The longer you let the area cool down the more likely they are going to snap.)

I’ve tried both methods, and honestly… either one works well.
Some techs want to use an injector cleaner in the engine a day or a few hours before changing the plugs.  I’ve tried that.  Yea, it works.  But it means putting in some extra time and money into the project.

  The first V8 that I changed plugs in I used the OEM method.  (Broke 3 plugs.) 
With the impact method I’ve broke one, only because I waited too long to get it out. 
I’ve done several since then and I haven’t had a bit of trouble getting them out.

   There are a lot of manufacturers and dealers for the removal tool. 
Snap on, Lisle, Napa, Ford, OTC, and many others. 
The tool works great; ya just got to get use to the awful grinding and ceramic shattering noises that you’ll hear.  (Nobody likes to hear that sort of thing over top of an open combustion chamber.)

As you can see the two methods are completely different, one with a cold engine and one with a warm engine.  One with gentle back and forth turns while the other is just plain brute force.  This is one time (in my opinion) that the brute force method works better.  There are probably a few more variations on these two methods; you’ll just have to find the one that works the best for you. The engineers may design them, but mechanics still fix em’. 

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