I have a question. I own a 98 Expedition with a 5.4 engine. I have right at 130,000 miles and I think it is time for some work. I have a couple of questions.
1. Original plugs. With everyhting I've read, I'm leary about having these changed and suddenly "blowing" a plug!
2. Is it a good idea to have the injection system cleaned?
3. Should I begin using synthetic oils?
4. Should I have the transmission filter changed?
I have to admit, I do nothing to this truck. I gas it, add a quart of oil between changes, and drive it like a redheaded stepchild. I've never had to replace anything with the exception of both the pads and shocks once. I think some things are obvious, however it sure is hard to spend money when it appears it does not need it.
BTW-Best vehicle I've ever owned.

 

Question 1. If you have not changed the plugs yet, I would think that they are due and you may be losing performance as a result. on the other hand, having gone soo long without changing may have lead to significant carbon buildup on the plugs. I would run some SEAFOAM through the engine and have a dealer change the plugs (if there is a problem, they are better target for resolving the issue).

Question 2 - Seafoam will help clean the fuel system. I would also suggest changing your fuel filter (more frequently too).

Question 3 - If you have 130,000 trouble free miles, I would stick with what is currently working.

Question 4 - yes, change the filter, or have the tranny flushed.

A final thought, please put some new tires on that rig to help keep the rest of us safe!!!!

 

Thanks for the info. I will try the seafoam and likely have the dealer change the plugs. Hopefully they will offer a decent warranty incase I blow one out. And by the way, the tires are decent! Thanks again.

 

dont go to the dealer.. there is no warrenty for blow out plugs. it can blow 5 miles down the road and they wont do a thing. they just told me its something that happens when it happens well tough shiit. so i would just do it yourself.. not hard just time consuming.

 

1. Use Motorcraft plugs, tighten them properly *with no anti seize on the threads* and you'll be fine. When I say "properly," I don't mean with a torque wrench; hell, ain't no way to get a torque wrench easily onto the two rearmost cylinders on either side. I run them down until they bottom out, then go another 1/8 of a turn. Never had a problem.

2. Fuels nowadays have all the cleaners and detergents in them you'll need. Most of the stuff you buy at the local parts store and dump in the tank don't do jack. The only injector cleaning system I recommend is Motorvac. I know lots of guys on here swear by Seafoam, but the way that it's introduced into the engine sounds like hydrolock waiting to happen if you get carried away with it.

3. If it ain't broke...don't break it.

4. Yes, a transmission filter and full service is a good idea.

 

I agree with Quintin, However I use Anti-Sieze(personal preference) - I have close to 200k on my 98 5.4L and changed out my plugs 3 times the last two without issues. -VERY important , ALWAY'S use motorcrafts, don't learn the hard way - Used the Seafoam method myself, but believe the motorvac service to be much better , it's more expensive - I think it's worth it.
It's hard trusting the dealership, given the history of these modular motors I would suspect everyone that works on them knows the proper procedures and how picky they can be, it's a roll of the dice with the dealership. If your mechanically inclined enough to changout your own plugs I would do it yourself to make sure all of the bases get covered(Use di-electric grease!!). Sometimes having this done or doing it yourself can cause hidden problems to come out in the open. If so come back here and let us know.

Good Luck - The 5.4L modular is an AWESOME motor!!! Take care of her ( :