A few weeks ago I posted about blowing a spark plug out of my 4.6. It amazed me that after visiting 9 different shops, I could not convince any of them to install inserts into all 8 cylinders. Every shop said it was a waste of money, yet every one of them admitted that these engines will usually blow out 1 OR 2 more in its life.

After making a second round & talking to all of them, almost all of them said that the plugs do not just blow out, but they actually slowly un-screw, then blow out taking only the top few threads with them. Simply re-torquing them every 20-30k miles will almost guarantee they will never blow out. They also added that while they are doing repairs, they have found many that had a few other loose plugs, & tightened them. Those trucks never came back for a second repair.

This sounds reasonable to me, as I started hearing a slight ticking sound a week or so before it blew the plug. I was meaning to check on it, but never did. Of course, now that it is fixed, the ticking is gone. Must have been a loose plug!!

What I find interesting is that this information NEVER came up during the 2 weeks that I was searching for proper repair info. The fact that this problem could possibly be avoided by re-checking the torque on the plugs every 30k miles should be posted on every ford page you read.


I am posting this because I am really looking forward to everyone's opinion on this. Maybe this info is out & I just never found it?

Discuss!!




Other thread:

https://www.ford-trucks.com/forums/1...lug-today.html

 

I changed my plugs about 3 months ago and was a nurvouse wreck. But it turned out to only be a 2 beer job and i got all worked up for nothing. I am due for an oil change next month and the plugs were so easy i will check torque on the plugs again. And i will just check them at every oil change, they are that easy so why not. One thing about removing coils, keep a spair because every once in a while upon removing the coil the spring breaks. When i changed my plugs i had 3 loose plugs and broke one spring on the coil. Glad i changed them.

 

That's what I am expecting to hear from many people!

Last time I did the plugs, I also found it easy. The secret is a flexible head ratchet.

 

Most of the blown plug issues are on the 97-01 5.4L motors.
The heads had a low number of threads in their castings.
While it seems there was also an issue with low plug torque, most of the issue is with the threads.
Once the plug and or thread material gives way it generally goes with such force from combustion/compression that the coil gets blown off the head with it.
If a ticking noise is heard, the plug has backed out far enough for combustion gasses to escape before the plug is physically blown out of the plug well.
There has been a low number of reports of blown plugs on the 4.6L likely due to plug torque issues rather than head threads issues.
Over time both engines got mistakenly thrown into the mix for the blown plug issue.
As of later in the 02 model year, the 5.4L 'head casting' issue has been solved by Ford with an improved casting.
On my 02 4.6L motor now with 219,000 miles, I have changed plugs about 4 or 5 times for various reasons none of which was due to plug torque of tread issues.
.
Changing plugs more often keeps the performance much sharper such that the less expensive plugs serve quite well for the application over the shorter intervals, Autolites worked very well having used several sets to prove a point on a rolling lab basis.
This last plug change, the Autiolites had more than .100" gaps after nearly 100k and the motor still ran perfect with no significant high counts in the mode 6, test 53 misfire monitors for any cylinder.
A new set of Autolites are now in place with several thousand miles and periodically checked for misfire counts that show nothing of any significance.
It is a 'perpetuated' myth that any other plug but Motor Craft 'must not' be used. As long as the correct heat range and thread design is used, boots are in good condition and hardware is all installed correctly and coils are not faulty.
I see there are many times owners claim the use of these plugs resulted in trouble that cleared after replacing them with MC. This is where the circumstantial evidence is taken as firm fact by a single appearance that is never actually proved to be caused the plugs by themselves.
I have simply not saw any evidence of this over the years and mileage trying to be scientific about it.
Good luck.

 

Excellent info here. Thanks all!

 

You say the plug boss casting was changed in 02' to more threads per inch. I had thought the same, but recently heard that the TPI change took place in late 03' on the 5.4L?

 

Everything I have read says mid '03 also, but never read from any official source. Saw on some site anything engine made after 12/02 was an 8 thread head.

Maybe he was referring to the mid '03 model year, which is towards the end of '02?

 

Supposedly it is '03 but even the 8 threaders can spit a plug. MY '08 CVPI spit one a while back. Luckily it threaded back in. Should have known, after my '97 did it twice I knew the noise and still didn't check plug torque in time before it blew. Several others have also had the 8 thread heads spit on this site and others.

 

Wish I'd read this 2 months ago! I got a ticking, and assumed it was the dreaded ford lifter tick. Until I blew 2 plugs, and a coil pack right off my motor. Reassurance from the parts guy, that 5.4's are famous for that! Didn't make it any cheaper to fix, as I replaced all 8 plugs and packs.

 

I wonder why no one else is having this problem (other manufacturers) with aluminum heads. Is it just that they weren't torqued enough, or are the post TSB new torque 28ft lbs. plugs coming loose to? I've been using steel spark plugs in most every kind of aluminum outdoor power equipment most of my life and have never seen one even come loose, we're talking thousands of engines I've worked on as a mechanic. Is it the torque alone or was there a problem with the bevel the plug mates with not being the same. Maybe the aluminum itself is softer? I'm wondering now if I should have all 8 of my newer engines plug wells "time-serted" before I install it, while it's still out. I put 203,000 on my 5.4L and never had a plug problem.

 

i swear my 02 4.6 only has 1 1/2 threads.. I put in the plugs and it seemed they bottomed in a turn or two.. I was like "wow" the first time i did them.

I torqued mine to 14ft lbs.. Where does it say to go more or was that just for the 5.4 ?

 

Not sure about the 4.6. But I believe I read in the how to change your spark plugs thread they say ford issued a TSB at some point and recommended the upping the torque to 28ft-lb

 

Shouldn't be any different for a 4.6, it is the same head.