Changing spark plugs in '97 5.4

[Shadetree]

After reading all the horror stories about doing a plug change in my '97 5.4 I had decided to take it to the local dealer. I called and they quoted $560.00 to change the plugs...Is it really that tough and they are earning the money, or am I getting shafted? I have changed my own plugs for over 50 years but it used to be a 30 minute, no brainer, job...

I took it to the dealer at about 100 k for a recall fix and had asked them to do a tune up while it was there...I never gave it any thought until it started idling a little rough recently. I checked my records and the receipt says nothing about a plug change...I'm assuming it now has 157,000 miles on the factory plugs...I'm thinking about changing them myself because of the cost.. My question is, should I bite the bullet and let a pro do it, or do it myself...What should I be most concerned about....Thanks

 

[SOLISIMO]

Some guys in here are hard core diy'rs. I have also heard of horror storys and it being a pain in the a55. Ill let some of the 1st gen guys chime in on this but I will tell you that on mine, the dealer will be doing it when it comes time.

 

[Thermo]

Shadetree, call me a hard core DIY'er, but doing the plugs isn't that bad. Yes, it takes time and you will need to have three 3" extensions. A 6" or 9" extension will not work. TRUST ME!!!!!! Having some flexible joints for your ratchet is somewhat helpful too. I would also tell you to spend the extra $5 and get a box of fuel injector O-rings. When you pull the fuel rail (makes the job much easier), it is very common for the o-ring to roll off of the injector and invariably it will fall down into the valley of the motor.

As for things to watch out for. You want the plugs snug, but not overly tight. too little torque, they will back out and you blow a plug out. Too tight and you stress the aluminum threads and the plug blows out. I seem to recall the proper torque is 15 ft-lbs. After that, do a good inspection of the tops of the COPs for any cracking (replace if they are cracked) and then also look at the rubber boots and make sure that they are in good shape (if not, you can buy just the boots and replace the ones that need to be).

What you will find is the front 4 plugs (2 on each side) are super simple and will take no time to get done. The back 4, well, that will be your challenge. That is where the 3 short extensions come into play due to the limited overhead clearance (much easier if you have a body lift installed). Those will take you about 30 minutes each in just trying to position your body right so you can drop the socket and 1 extension into the hole, add a second extension, then finally dropping the final extension and socket on to the plug. I normally found I could get 2 extensions on the socket and put that on to the plug and that whole assembly would be just about flush with the top of the head. From there you can bring in your ratchet to do the work.

Save your money and get quality double platinum plugs. The "multi-spark" plugs (Bosch +4's, +2's, Splitfires, etc) don't do anything for our trucks. ALl they do is lighten your wallet.

 

[dougmcp]

I have done my plugs in about 3 hours and it's not that difficult.

There are only 3 threads in the head that hold the plugs, with 157K miles the probability of carbon build up on the plug threads is likely so you will need to be careful.

There is a service bulletin and procedure from Ford specifically for these engines:
The TSB from Ford is here: http://www.phila.gov/fleet/Warranty%20Recalls/tsb08-07-06%20FORD.pdf

Here is the most important part:

CAUTION
DO NOT REMOVE PLUGS WHEN THE ENGINE IS WARM OR HOT. THE ENGINE MUST BE AT ROOM TEMPERATURE WHEN PERFORMING SPARK PLUG SERVICE. REMOVING THE SPARK PLUGS FROM A WARM/HOT ENGINE INCREASES THE CHANCE THE THREADS COULD BE DAMAGED.

Spark Plug Removal Procedure:
1. Remove the coil-on-plug assemblies and thoroughly blow out the spark plug wells and surrounding valve cover area with compressed air.
2. Back out the spark plugs no more than 1/8 to 1/4 of a turn.
Using Motorcraft Carburetor Tune-Up Cleaner, fill the spark plug well just above where the jamb nut hex sits (1/2 - 3/4 teaspoon).
A minimum period of 15 minutes of soak time is required. The cleaner will wick down to the ground electrode shield and soften the carbon deposits in this time. DO NOT WORK the spark plug back and forth at this point.

 

[superexpy]

I do mine about 2 - 3 times a year with out issue for the past 10 years. Just dont under or over tighten them.

 

[dougmcp]

I do mine about 2 - 3 times a year with out issue for the past 10 years. Just dont under or over tighten them.

You must drive a lot of miles.
That's certainly more than the once every 10 years I do mine.

 

[BakerEdition]

I do mine about 2 - 3 times a year with out issue for the past 10 years. Just dont under or over tighten them.

Question...How do you under tighten something?...is this a southern thing?

 

[dougmcp]

Question...How do you under tighten something?...is this a southern thing?

Under tightening is from the bottom and over tightening is from the top, I've done this many times.

 

[Thermo]

Baker, like with the spark plugs we are talking about, they are supposed to be tightened to 15 ft-lbs (as I recall). If you overtighten them (ie, take them up to say 20 ft-lbs), what you are doing is effectively pulling the threads out of the head (we are talking on the scale of 0.0001" or so), but it is still stressing the threads. The metal can only take so much stress before it finally gives. Now, keep in mind that when the cylinder fires, you are going to have a certain added stress being applied outwards (in the same direction as the overtorquing). This is what leads to the failure that way.

Now, for undertorquing, this doesn't seem quite so logical. But, in short, when you under torque something, you are not putting a significant amount of stress on the mounting surface (threads of the head in this case). So, the item that you are tightening can move around some (again, we are talking on the scale of 0.0001"). But this repeated moving of the plug (with each firing of the cylinder) will cause either 1) the spark plug to start to rotate, which then will cause it to get less and less torque and lead to it unscrewing itself, or 2) the plug doesn't rotate, but the metal is being hammered over and over which leads to accumulated stresses in the metal due to the "hammering", which will cause the metal to become weaker, leading to a sudden failure.

So, when you look at torquing items, you need it tight enough so the item doesn't move when it is stressed, but not so tight that it puts undo stress on the metal. Where a lot of people mess up is when they think they are doing a good thing and apply a lubricant to a bolt as they torque it (when it should be dry). Apply this lubricant causes the fastener to rotate easier. This will cause the fastener to see more torque (the friction preventing the dry fastener from rotating eats up some of the torque that is ultimately applied to the fastener). More torque, more stress on the fastener/metal surrounding, the more likely it is to fail due to too much stress.

I can go into more detail on this subject. I worked as a quality assurance specialist for awhile and I had to become very intimate with how torque affects various joints and how to ensure the proper amount of torque was applied. I used to have manuals upon manuals on various threaded materials being threaded into other materials with an assortment of lubricants applied. Needless to say, finding the right torque for something (when it is a very critical thing) can be a very detailed process.

The big thing to keep in mind is that metal actually gets slightly stronger when it is stressed slightly. The trick is that if you apply too much stress it will fail catastrophically.

 

[jrjr]

The front plugs are pretty straight forward but when we get to the back ones and have to use a flex joint of one kind or another, that changes torque values and/or renders the applied torque inaccurate as I understand it. So do we just 'calibrate' our body and just do the closest we can by feel?

Kind of a rock/hard place scenario I guess.