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Fouling in the spark plug well

So, sure 'nuff, there IS such a thing as too much of a good thing. Instead of using spark plug anti-seize sparingly on the first couple of threads, as I was advised to do, I went ahead and lightly (or so I thought) coated the whole of the thread. That was at least a year ago.
Last week, after my car started missing and it got progressively worse, I took it into the shop. After getting it fixed, the shop’s customer rep. told me that the damage was some kind of goop fouling the spark plug and causing damage to the coil head. He also said that the mechanic checked, and the fouling was to be found in all of the spark plug wells. Needless to say, potentially all of my sparks can suffer from the same problem, and damage their coils.
Of course the solution is simply to clean the goop off the spark plugs and the spring in the boot that connects it to the coil, if fouled. And, in order to avoid the goop falling through the spark plugs hole into the cylinder, I should first clean out the well. But I worry about not being experienced enough to do this without somehow making the problem worse. So, ANY ADVICE OUT THERE? I’d REALLY appreciate it!

P.S.: I neglected to say that I went in to a couple of the spark plug wells with a thin dowel wrapped in a rag, and sure enough found the goop down there as advertised. And, despite being mixed other gunk, it sure did look a lot like the anti-seize grease I’d used on the sparks.

I’m just guessing, and I don’t know if it would work, but could you unplug the coil-over, leave the plug in place, and squirt a bit of carb cleaner down by the plug, then wipe it out like you tried already, or blow it out with compressed air or canned stuff you use to blow dust out of electronic parts?

All these solvents are toxic and explosive, so be very careful, and do it outside, wearing eye protection.



Which Engine?

You presented a problem you’re having with the engine. This information would possibly be helpful and a good place to start.

“So, ANY ADVICE OUT THERE? I’d REALLY appreciate it!”

With the additional information supplied, I’ll give it a shot.

Hi, west. This what you describe is my plan, so far. But just like I blew it with the with the anti-seize grease, I want to make sure there isn’t a hidden reason not to do it. E.g.: The carb cleaner doesn’t damage the spark plug seat/seal.

Hi, CSA.
It’s a 2006 GT, 4.6 V-8 engine.

The anti-seize did not cause this problem. It sounds like you’re describing the spark plug wells as having motor oil in them and that is caused by aged and leaking valve cover gaskets. The new gasket set will have new plug well seals.
If this goop you refer to it as is corrosion, then that is caused by moisture in the air. Your best bet there is to replace the plugs and possibly the coils while using the special dielectric grease in the plug boots.

You need some compressed air to blow out the plug wells before removing the spark plugs. Don’t worry about small bits of debris falling into the cylinders. That will be incinerated and blown out the exhaust in a few seconds.

Thanks for the feedback.

You have the right plan. Solvents won’t hurt the spark plug seats but you don’t want to trap the fliud inside the cylinder. Blow it out and let it air-dry and all should be well. I understand WHY you used a bunch of anti-seize … these engine have a tendency to break off the spark plugs when they get gummed up with combustion product. Congrats on not having to use the special tool to extract the broken plugs but go easy on the anti-seize with new plugs. It only need go on the first couple of threads as you found out…

Thanks for the feedback, Mustangman.

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You might be able to clean the threads out using a back tap.

The tap works thusly:
the treaded end is trifurcated and closes smaller than the threaded hole. The tap is inserted in its collapsed state. When the nut on the top is tightened, it draws the cone up inside the tap and opens the “fingers” to the correct size. The tap is then gently drawn back up through the hole, drawing any contamination back out of the hole with it.

NOTE: lube the tap with oil before using. 3-in-one is fine, as is dipping it in motor oil. I don’t know if the instructions say to (I never read mine), but cutting heads should always be lubed, and the cone is much more likely to cleanly get drawn up the tap’s barrel.

Also know that you can find the correct size for your vehicle by looking up it’s OEM replacement spark plugs. NGK gives all the technical information if you look for it (you look it up by the spark plug number, which is a coded technical reference), and I assume other manufacturers do too.

I find an old tooth brush works very well for this situation. Cut the bristles short so you can insert the tooth brush into the hole without the bristles touching the threads, then push the bristles into the threads and “Unscrew” the tooth brush. Clean with solvent and move onto the next one.

Not all spark plugs need anti-seize, in fact it can be counter productive on some plugs like NGK that use an anti-seize plating. The black oxide coated Autolite do need an anti-seize. When you use anti-seize, you can cover all the threads but make sure that none of it gets past the threads towards the tip, thats when it causes problems.

Use a dielectric grease in the boot of the coil or the boot of the spark plug wire. It will help prevent arcing from the plug to the head. Do not worry if the dielectric grease gets on the conductors, it will conduct through the grease when it is in “thin film” and insulate in “thick film”.