My 2005 STX 4x4 (4.6 L) has 95k miles on it (runing great) and is ready for a tune up and replacement of a few other normal wear items like the serpentine belt, idler, etc.

I went shopping for plugs and wires. Will be going with all OEM stuff (Motorcraft) and will use the SP493 Platinum tipped plugs, since I've gotten great service from the originals.

The plug wires have presented me with a bit of a mystery though and I'm hoping you all can help.

In researching the replacement plug wires, I find that the catalog only lists 7 Motorcraft numbers: WR5923 (#3); WR5926 (#7); WR5928 (#1); WR5929 (#8); WR5930 (#6); WR5932 (#4); WR5933(#5).

Anybody know why it doesn't list a replacement wire for #2?

Also, I asked the local mechanic what he'd charge to replace the plugs...He is very concerned about Ford modular engines' propensity to have the plugs sieze in the heads. My truck is a 4.6L. Isn't that problem specific to the 5.4Ls?

Thanks in advance.

 

Hi.

Not surprising as you Have NO plug wires - you have a COP ignition (coil-on-plug) - one individual ignition coil per plug - directly on top of it. No distributor, bupkis.

No plug seizures either - that was for 5.4L 3V's.

Don't forget to buy new boots and springs and use dielectric grease properly.

BTW - don't fergit to change the fuel filter and be sure to inspect the FPDM. How-To's available for both in our Tech Articles Section. Same goes fer the plug change itself.

good luck

 

Thanks for the quick response.

I have little experience with modern engines...As they tend to need little maintenance like my old 60s car do, so please bear with me.

I did know that there were individual coils for each plug, but after doing a search on several parts websites -- including FordParts.com, it yielded a part that was referred to as an "ignition wire" by Motorcraft...and it listed 7 of them - each of a different length. Could that really refer to the boot you described?

And, yes, I'd always heard that it was the 5.4s that had the plug seizure problem exclusively... but in preparing to do the job, searched this site -- just to be sure. What I found were a huge string of posts on the siezures - which quoted a service bulletin as saying the 4.6s as well.

Again, thanks for your help!

 

If I could pick your brain just a bit more...

Here is the thread that referred to plug siezures on 4.6 engines as well. It mentions 3v. Would that exclude my truck?
https://www.f150online.com/forums/v8...g-removal.html

Also, here is how Rockauto and FordParts described the individual wires:

Applications: MOTORCRAFT WR5926 Spark Plug Wire
FORD CROWN VICTORIA (1997 - 1998)
FORD EXPEDITION 2002
FORD F-150 (1997 - 2008)
FORD F-150 HERITAGE 2004
FORD F-250 (1997 - 2008)
LINCOLN TOWN CAR (1997 - 1998)
MERCURY GRAND MARQUIS 1999

Having found the 7 listed as plug wires on several sites, I made an assumption that this was a normal wear item...Sounds like it probably is not, though.

Thanks again for your help.

 

No, your 4.6 is not a 3v, so no problem with changing plugs. All boots are the same and the only wires involved go to the COPs. You don't change them. As mentioned, just change the plugs and the boots.

 

You can buy the boots and the plugs at just about any parts store - stick with Motorcraft plugs but aftermarket boots are fine as long as they are a reputable brand.

Like everyone else says, you do not have plug wires, trust me.

Spark plugs should be torqued to 28 ft/lb WITHOUT antiseize. Motorcraft plugs have nickel-plated threads and do not need it. Use of it can lead to plugs coming loose by themselves.