If this has been covered I appologize. Sorry to be so ignorant but now is the time to learn.

Question: Re the 1998 Expedition with the 5.6 liter V8. Is it true that instead of the traditional coil and wire leads to each spark plug there is a small individual coil for each spark plug (eight in total)?

Is it true that the plugs are good for 100,000 miles and are very expensive to replace?

Is it true that excessive spark plug wear causes increased electrical resistance thatr can prematurely wear out the individual ingition coils?

Is a certain mechanic giving me a lot of hooey?

Sorry, I can't look under the hood. The wife is off with the Expedition and I can't remember what the arrangement under the hood looks like.

All comments, suggestions, and information are appreciated.

 

Correct there are 1 per sparkplug, 8 coils total.

Incorrect, the sparkplugs cost the same as any other sparkplugs there is nothing special about them though Motorcraft plugs (same as factory installed) are recommended to use as replacements. Now the COILS on the other hand are expensive they range around $50 EACH. The sparkplugs are rated for 100k, but your mileage may vary. I had to replace mine at 80k, and then again recently at 130k when i had a sparkplug eject out of the head and through it's coil, but that's a whole different subject...

Well sure, excessive sparkplug wear is never a good thing.

Not sure if he is or isn't. If he's stating that you have 8 coils to deal with and they are expensive to replace he's telling the truth. If he claims that the head on the 5.4L Expy is a poor design and is know to eject sparkplugs, he's telling the truth. If he claims that changing the sparkplugs is a pain in the butt, he's telling the truth....

You can do a search of these forums and find out all kinds of information about the arrangement you have under the hood of your expy as well as issues that engine has. I've read plenty of horror stories, and plenty of stories of people having no issues at all.

 

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Thank you Pondscum.

I did not know about the head problem. Is this sparkplug missle program the result of an alloy that is too weak to hold the threading of the spark plugs?

This particular mechanic told me the spark plugs will cost me $15 each which seemed absurd since the price quote at the parts store was around $3.80 a piece.

It pays to shop around and stay in touch with this website.

Hope I can do something for you some day.

Note: I checked some of the postings in the Engine Forum. Yes, tehre is a ral problem with four threads securing a spark plug in an alloy head.

So much for the after market supercharger we were thinking of adding.

 

I did not know about the head problem. Is this sparkplug missle program the result of an alloy that is too weak to hold the threading of the spark plugs?

Note: I checked some of the postings in the Engine Forum. Yes, tehre is a ral problem with four threads securing a spark plug in an alloy head.

So much for the after market supercharger we were thinking of adding.[/QUOTE]
That's another myth! Maybe some people can't install plugs the right way-for example you must blow the plug area with high pressure air before removing-and also you should apply never seize to the new plug threads.