Hi,
I'm approaching 100000 miles on my Navigator, it has the DOHC 5.4 in it, I know it is recommended I replace the plugs at 100000. My local ford dealer wants 530.00 for the job, when i asked them if that covers any plugs that would break they said no that would be extra and stated the job could cost upto 2000 if all 8 broke as they would have to do a head job. I laughed and hung up. My qusetion is how many people have actually had there plugs break on this forum and did they repair them themself or have a shop do it. I have done many plug changes but never on this type of motor. thanks giovanni

 

You can do the job yourself and save the money. You just need to have time on your hands - to be honest.

I'm not sure if the amount of threads per spark plug is different as compared to the SOHC 5.4s, but if you can, spray penetrating oil down each of the plug wells and let it sit for a day before trying to remove the plugs.

If the DOHC heads have more threads per spark plug like the 3V 5.4s, I think I've read that the guys in the Super Duty section run Marvel Mystery oil in there truck a few days before starting the job, and the reported success rate for removing plugs without breaking has been very good.

Both ways, if you can be without the vehicle for a few days while you do the job, I'd let it sit and spray some PB Blaster or something along those lines be patient while it soaks around the plugs.

Just a thought.

 

DOHC 5.4L's have "full thread" heads, but DO NOT have a problem with plugs breaking off in the heads. That's an issue with the 3V plugs from '04-'07 before they redesigned them.
JL

 

Just got a quote from the stealership of $295 for spark plug change.Parts and labor for my 01 expy,I think its fair.

 

i just replaced my plugs on my 00 expy myself for around 30$

 

Thanks, for the information, ill attempt the change this weekend. Just wondering why the dealer told me they had issues with this head and spark plug.

 

i didn't have any issues with replacing my plugs.
plug #4 is just hard to get to i used a 4 inc. extension than a 6 inc. extension a swivel and a 10 inc. extension and it worked great.
i recommend using bosch spark plugs.
good luck