xMUDKINGx

Alright gentlemen, I come to you in need of help, I have a 07 XL with the 4.6 and it keeps ejecting spark plugs, back in March it spit one out on the drivers side, I paid a shop 100 bucks to helicoil it and I thought it was over, well yesterday it happened again on the passenger side. This time destroying the coil over plug on top of it, it sent the spring shooting out of the rubber boot, well I ran to the auto parts store got new plugs and a new cop but the threads on number 3 are gone, so naturally I'm thinking of another helicoil to fix it. Thankfully it happened right down the street and I knew what it was right off the bat so I didn't have to pay for a tow or anything crazy like that, has anyone came to a reasonable fix to this issue that I can do preventively so I don't have this issue down the road? Any help is appreciated


-xMUDKINGx

redfishtd

I am surprised to hear of such a thing on this late model . The improved heads are supposed to be on this model . Before the 05 heads they had too few threads on spark holes . That was understandable .
Are you starting these plugs by hand as you should . Are you torquing them in to the proper torque .
I have the 5.4l 3v so I'm not up on your torque values so I won't quote any numbers .
You realize these are alum heads and threads ,very touchy, no impact tools for installation .Cross threading is very easy to screw up . I don't use power tools on sparkplugs . Clean out sparkplug holes with air and or vacuum before going in there .
I have helped put inserts in a 98 5.4 l 4v navigator , with a special tool . I would not use a helicoil they can't handle the heating/ cooling .
Timesert is the Cadillac of inserts but the tools are expensive . Inserts are high temperature thread locked in and need at least 4 hours to set up after proper installation .
https://www.amazon.com/LocTite-Threa.../dp/B003WRH8DA
http://www.timesert.com/
You must be knowledgeable about the steps or use an experenced mechanic to get the shavings out of the holes and pistons and not drill hole in the piston .
Sounds like someone used power tools on yours or didn't use a torque wrench . You can't even trust the oil change shops from cross-threading your steel oil pan drain . They will swear it was that way when it came in .

screamineagle

Helicoil is not the proper fix and will not last. An insert is a permanent fix. Improper torque is the reason for the blowout.

xMUDKINGx

As far as the torque spec goes, it's 11 foot pounds, not very much at all, however I have never changed my spark plugs myself, the last time they were changed was sometime last year while it was in the shop getting the transmission rebuilt. But it wouldn't surprise me if they didn't know what they were doing. My spark plug passages also had a lot of dirt built up inside of them, I'm not sure if maybe that had anything to do with it.

xMUDKINGx

Does anyone think it's worth while to just try to re-tap the hole and see if it goes in for me? I can't even get the spark plug to start threading

Martian

I actually think that's been done before... I'll try and find a thread on it

Martian

Found this.

xMUDKINGx

I'm thinking I'll try to get a tap and rethread it before I go the time sert route. At the very least just get it drivable to make it to a shop that can time sert it for me.

Martian

Whatever works for you, friend.

joe mcmillan

Looking on line I find varying posts on forums and from various manuals showing torque specs for 4.6 2 valve engines from 11 to 28 lb ft.
When I replaced mine (2004) there had been a post suggesting to tighten 1/4 turn after snug. I used this procedure. All plugs tightened nicely and none have come loose.
Not scientific but good results.