My V8 sparkplug story | Ford Explorer Forums - Serious Explorations

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My V8 sparkplug story


November 28, 2011
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Year, Model & Trim Level
2006 Explorer V8 AWD
Yes another sparkplug thread, but I'm sure there are people still on the fence about tackling this themselves.

The patient is a 2006 Explorer. We bought it in 2011 with 80k miles. It's now at 96k mostly multiple short trips, prime candidate for carbon buildup. I used a bottle of seafoam just prior to the operation and tried to get as much highway miles as I could.

Even then, I had the worst of luck. Even following the TSB diligently, I only removed 3 plugs intact. The Lisle tool is a godsend. I used it on 5 broken plugs and the cutting thread on the extractor part still looks like it has life left.

So I started on a Friday evening by spraying a small amount of penetrant into each plug hole. I let it sit over night. I then soaked it up the residual penetrant and sprayed each hole with carb cleaner until it just covered the hex head as per TSB. I let it sit for a couple of hours. Then I backed out each plug 1/4 turn. Let it sit another couple of hours. I then started slowly backing out plug #8 with a little back and forth when the resistance seemed higher. The first plug broke, omen of things to come. This one broke right where the lower metal sheath ends, perfect for the Lisle tools. After using the tool once, it becomes second nature.

The next two came out intact. Then another broken plug, same as the first. This continued until the last two plugs. This time, the hex and the thread came out, but the porcelain core remained intact. I ended up taking a long screwdriver and cracked the porcelain. Luckily, on both plugs, it broke just above the lower sheath, perfect position for the Lisle tool.

So after 5 broken plugs, and 5+ hours of wrenching (a lot of panicking and cursing) I was able to remove all the plugs. I replaced them with new SP514 plugs coated in good quantity of nickel anti-seize on the lower metal shaft and capped off with MSD COPs (the ones originally on the truck were a mish-mash of motorcraft and 3 aftermarket ones, so I just decided to replace the whole lot).

There is no more sputtering and flashing wrench when I go WOT. Truck runs so smooth and feels the best it ever has. MPGs have increased tremendously. I was averaging 11.7mpg (yes, should have done this sooner) and now it has jumped to 17 which I'm extremely happy with.

The head design and the sparkplug design is probably the most idiotic I've ever come across. I've never had this much trouble changing sparkplugs before. This truck is the last FoMoCo purchase I will ever make.

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Toked... I understand your frustration, but this design was only used for 2.5 years before Ford fixed the problem so don't let this one bad design let you think that all their vehicles are built this way. Besides all the manufacturers have had some design flaw over the years to the vehicles that they produce.

I was planning to do my own plugs on my '06 V8 and I thought "maybe check online first, just case." I couldn't believe how bad the spark plug design and subsequent issues were!

So I took it to the dealer and he said they had very good results with the impact method of removal and they did mine with no issues.

I don't know why the impact method works better than removing with a hand driven wrench, maybe it's the hammer action?

Also a hot engine like in the video might help?

All makes and models have their frustrating idiosyncrasies, maybe Ford as a few more than most, I don't know. For me if I feel like there is something weird I go to the dealer figuring they should know more about it than anyone. Not everyone has that option I know, I think this forum is good place to refer to also.

Anyway, it sounds like you did a great job even though it was a PITA. Changing plugs should be easy, c'mon Ford!

The heater blender door was another head scratcher... don't get me started on that one...

Good luck with the new plugs!

I wrote my first post out of frustration. I never expect a car to be trouble free, but something as straight forward as changing plugs? C'mon, that's just regular maintenance. I've wrenched on most of my/family cars before, from Toyota/Lexus to Cadillac to Mazda to Mercedes to Dodge to Ford. I grew up working on my friend's 95 5.0 Mustang. All have had their fair share of issues. On some, gaining access to the plugs might have been difficult but never an issue like this which is clearly a design/engineering flaw. I purchased this Explorer to be a workhorse for cheap.

Before doing the plug change and following the TSB, I had been chatting with a fellow Triton owner and his ordeal at the dealer after they used the impact method and the astronomical bill he was handed. I have an impact wrench on hand, but seemed counter-intuitive. Either way, I'm now out of the woods and will be removing, cleaning, and regreasing the plugs every other year or so. I plan on keeping this truck for a long time before getting rid of it.

So far the truck feels better than when I got it (it was 80k miles old) and am happy with my handiwork so there's that. And since I spent less than $500 for everything including all COPs, plugs, Lisle tool and other items, I'm just going to enjoy it for now.

i was lucky. i changed them at 85000 after reading about the stupid design and history of problems with the v8. i was able to remove all 8 plugs without breaking one of them. took me about 8hrs though.

I'm thinking about getting an air compressor and impact gun, unrelated to this spark plug issue of course, but I have been looking into how they work.

It looks like the hammer/anvil mechanism is very effective at applying torque to solid/stiff masses by striking with the hammer, releasing and repeating.

My guess is the hammering is able to knock loose the carbon build up, which I'm thinking is strong but brittle. So hammering shatters the carbon, whereas a steady torquing force is not as effective.

I don't know how anyone would be able to figure this out in advance, I bet the Ford techs learned from a lot of trial and error.

Sounds like a good guess, Mark. It really makes no sense when you think about it. I watched a nimrod, rookie twist two lug nut studs off my old Chevy, because he had the torque set too high. And, I'm amazed how long the impact wrench hammers at the plug before it starts to work loose. I had one plug extraction fail because the torque was set too low. Either way, I'd NEVER attempt it without that Lisle tool at the ready!

My IR W7150 would love to try the impact trick. Hmm, wonder if it'll fit on the rear-most plugs because they are so close to the firewall.