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1998 Expedition XLT..Change Spark Plugs

03-20-2005, 08:49 AM
Hey y'all...........I'm new to this forum but I need help!!! I'm right in the middle of changing the plugs on wifey's 98 expedtion. I've got the extensions and swivels........but I don't see how I'm gonna get 2 closest to the firewall on both driver and passenger side. Can anybody help me????

03-20-2005, 03:04 PM
Not to sound stupid, but the way to do it is slowly and carefully. Just takes time and the right combination of extensions.

11-23-2007, 12:10 AM
Here is a good way I did it. I think I can change my Expedition spark plugs in less than an hour now. This method involves detaching the power connection near the firewall on the passenger side. It is well worth the 5 minutes extra it takes. Here are my verbatim instructions. If you want instruction with photos follow this link or the link at the bottom of this tutorial. (

The procedures for replacing/changing spark plugs on the Ford (, Lincoln Navigator, & F-150 Triton.

I just replaced my spark plugs on my 1998 Ford ( It was much harder than I'm used to (I have a 1989 Jeep Cherokee with the inline six, and I can change the plugs on that in about 10 minutes).
Anyways, I've outlined the procedures that I used. Don't rely on a store-bought repair manual as the instructions are way too vague.

Here are the instructions verbatim. If you want the instructions with photo examples just follow the link at the bottom.

Hope this helps,


I just finished up replacing the spark plugs on my 1998 Ford ( with the 5.4 Triton V8. (This was a pain in the @ss; I owned a 1990 Ford Thunderbird and I thought those were horrible). Anyways, after searching the internet I found some very good tips on several site forums. I used these tips along with some additional steps that I thought would definitely help make the task less stressful. The additional steps may seem extensive, but they help make the task much easier, and like I said, LESS STRESSFUL!
First off, don't bother relying on a store-bought repair manual like the one I own. The instructions are so vague, they pretty much just tell you to remove the coil packs and remove/replace the plugs.
The best method involves using a foam pad (or thick padded carpet) and setting it over the radiator and top of the engine. You'll need a stool or chair to secure your footing while lying across the engine ( on this.
You will need a good assortment of extentions and swivels in 1/4" & 3/8" drive if possible.
If done correctly, it should take between 1-2 hours.
First as usual, disconnect the neg. on the battery.

Lay the padding across the radiator/engine (

When doing this job you'll end up looking kinda like this.....(I recommend using something much more stable than this little stool I used).

Remove the plastic cover ( the throttle body. (Three 10mm bolts)

Remove power ( terminal cover ( the passenger side near the battery (this pops off when you pull downward & out at the bottom of it)

Remove three 13mm nuts and the cables. (make sure you mark them so you put them back where they were). Next, remove the two 8mm bolts holding the entire assembly to the firewall. Pull away from the firewall. Now you will be able to have easier access to the #4 spark plug farthest back on passenger side. I feel that this is the hardest one to change.

Remove the three 8mm bolts & remove the plate that secures the power ( reservoir in order to access the #5 spark plug.

Replace each spark plug one at a time. On the driver side you may need to remove the two 8mm bolts securing the fuel ( You may need to pull the fuel rail up and away slightly to clear the check valve and access the #6 spark plug. Make sure you blow away all debris before removing the fuel rail. You do not want anything falling into the manifold. This would be HORRIBLE! Also, only pull the fuel rail away as far as neccisary to access/remove the bolt securing the coil pack and the coil pack itself. Debris (or a dropped coil pack bolt)could possibly fall into the manifold through the injector ports! Again, this would be HORRIBLE!

Attach a small section of hose to reach the hard-to-reach areas. You need to blow out the spark plug holes BEFORE you remove the plugs to prevent debris from falling into the cylinders. And yes, this would be HORRIBLE!

Also, make sure you coat the spark plug threads with anti-seize, and coat the inside of the boots with dielectric grease. This will prevent corrosion, heat damage, and prevent the boots from sticking on the next replacement. Gap the plug to specs before installation.

After taking your time ( being patient, you will find yourself finishing up this job and feeling a great sense of accomplishment. Bolt all parts ( up to where they were, and re-check all of your connections to include connections to the coil packs, injectors, and also inspect surrounding vacuum hoses to see if they were accidently disconnected when moving them around to access the spark plugs (the PCV valve kept popping out when I did mine).

Hinesight is always 20/20, but I'm pretty sure I could do this again in under 1 hour. Remember, take your time, be patient, be careful, and take a breather if you need it!


here's the link to my web page with accompanying photos: (

03-25-2009, 09:00 AM
Just wanted to say thanks to Vic. I just changed the plugs on my 03 Expy, and your directions were spot on. Thanks again.

03-27-2009, 07:11 PM
There is a TSB on changing plugs on these.Warm it up firstat laest 45 minutes.Turn the plugs an 1/8th of a turn.Pour down Ford's special cleaner in th spark plug holes and let it soak overnight.The plugs will come out easier

11-27-2012, 12:41 PM
I know this post is old but I'm trying to change my 1997 Ford Expedition spark plugs and would like to see mister-v-man website but its no longer available. So I'm hoping he sees this and updates the link or possibly sends it to thanks

11-29-2012, 02:52 PM
I know this post is old but I'm trying to change my 1997 Ford Expedition spark plugs and would like to see mister-v-man website but its no longer available. So I'm hoping he sees this and updates the link or possibly sends it to thanks

Never mind, the link still works. It looks like the auto links to Ford and such are what are no longer there, but not a problem.

I hope to have an update to this and that it all worked out well.

01-14-2013, 09:25 AM
The plugs on my 98 turned into a nightmare. Last plug on passenger side snapped off leaving the threads in the heads. Had to remove the head to get it taken care of. Machine shop was able to get the threads out without damaging the head. Been reassembling the engine. Worst vehicle I have ever had to tear down. Found out that many raise the body off the chassis to access the engine. Without a lift that isn't easy. :crying:

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