I recently bought a '99 v10 Ford with 135,+++ miles. Was told by a shade tree mechanic that it looks like the plugs have never been changed.
The truck is running great, 13 miles to gallon at average 65-68 highway miles per hour.
Another local shop mechanic wanted to take a plug out and look at it to see what shape it was in. He said if it was in good shape put it back in and forget about it. Incidentally, this guy never heard of plug ejection problems in ford trucks. Crossed him off my list.
So question is... what should I do? Any way to tell if the plugs are original?
I live in Cape Coral, Florida. Any local recommendations for a reliable mechanic? Willing to travel some for a good mechanic.
Thanks much, Ron

 

Changing plugs will carry some "risks" that you need to understand .

1- During the removal of plug: If the plug is fused in the hole and forced out , there is a good chance of thread damage . This may be preventable by soaking the threads with some anti-rust sprays and work with patience ( not exactly a commercial shop environment ).

2-During installation of plug : If it is tightened by a gorilla or using air -gun with total disregard of recommended torque .

Keep these possibilities in mind . You may already know that your '99 V10 has older style heads with 4 spark plug threads, so these concerns are real .

Your 13 mpg @ 65-68 mph is acceptable . The mechanic's suggestion "remove one and check" not a bad idea ( check; 1- brand , is it motocraft ? 2- check plug style , is it old style plug ? 3- Check gap : is it about .052-.056 " ?) . The answers will tell you where you are .

Also , get yourself familiar with "Timesert" plug repair kit and the procedure at timesert.com. This is what you need to do IF the unfortunate thing happens ( a blown-up plug AFTER the plug change ) . Find yourself a shop familiar with timesert repair , just in case .
Good luck.

 

If the plugs are originals and have 135k+ miles on them they need changed. Your COP boots are probably not in the greatest shape either. Buy 10 Motorcraft SP479 plugs and change them. Its not a hard or difficult job to do properly, a little care is just needed. I'd just make sure to check to make sure the plugs are tight about 5k miles after the change.

 

If it were my truck....just change them so you know everything is right.

 

Is this something you're willing to do yourself? While its not overly complicated there are indeed some necessary steps required in order to do it successfully, that is without causing your own thread damage.

I have a somewhat extensive list of threads posted here previously which require a bit of reading but from them you can get a lot of information and confidence building ideas making it seem doable. I'm glad to post the list here if its of any interest.

 

I'm not physically capable of doing it myself. Besides being older than dirt I have some service connected problems that prevent me from doing it.
I am trying to get as much of you folks knowledge as I can so that I will be able to communicate with local shop mechanics... mainly to see if they appear to know what they are doing and know the problems with Ford plugs on V10s. Example, I was at a local shop the other day and asked the mechanic if he knew about fords having a problem with V10s throwing plugs and he said he never heard about it. Def do not want to use him.

 

Best way to tell is look down the hole with a flashlight at the plug itself. If it's all rusty, it's most likely an original plug, because replacement plugs after a certain point were all zinc plated and should rust (much).

If it were me, I'd do them NOW. Let them soak with some penetrating oil overnight. Crack them loose, but do NOT remove them. Put more oil down there. Wait a few hours. Loosen 1/4 or 1/2 turn and wait for the oil to penetrate more. DO NOT force them out.

After that few hours of waiting, blow out the holes with compressed air with a rag wrapped around the air chuck and against the hole. Make sure you get everything out, and then spray a little more oil down there and make sure the plugs are loose before pulling them out. And again, spray with more compressed air and a rag before fully removing them. There's bound to be a lot of crud down there and you want it all out so it doesn't fall into the cylinder.

 

Need someone to change my plugs in or near Fort Myers, Cape Coral, Florida.
Anyone know of a shop here that will do a good job? Thanks, Ron