Changing spark plugs on 4.6L V-8

[SyberTiger]

How hard is it to change the plugs on a year 2002 4.6L engine? Am I going to have to be double jointed to do this job? Is there a proceedure somewhere for this?

Should the plugs be torqued and if so how many ft-lbs? If not then how tight to put them in?

Last, I read a number of threads about AutoLite and Motocraft plugs. Bottom line, what plugs should I put back in?

 

[EasyRhino]

Lots of threads on this topic.

Answers (I hope):

Word is that it is not too hard on the 4.6, like none that require going through the fender liners, etc. The plugs are 'on top', not between the exhaust manifolds.

Be sure to do them cold (aluminum heads), have the proper 5/8 spark plug socket. You have to loosen and pull the coil packs (you have no spark plug wire sets/looms), and carefully move the injector rails aside. Takes a long extension to reach the plugs, I believe. Use air to blow out any crud in the bore before you pull the plug to keep the trash out of your engine, and use some penetrating fluid to ensure no thread damage when you pull them.

You will need to put anti-seize on the threads of the new plugs prior to install, and a length of rubber hose is handy to get the plugs started in the threaded bores before applying the wrench.

The word on this site is that the factory Motorcraft (aka Autolites) are the best replacement plugs - that's what I got.

My manual shows 156 in-lbs (or 18 NM) for the torque. IOW, not much.

If I get my act together in the next few weeks, I hope to put up a procedure with pictures, but my time is not necessarily my own.

 

[n2epv]

4.6 plug change

Can someone explain "move the injector rails aside"? Or can you unbolt each coil and tilt it outward (then pull up) to remove it. I haven't dealt with this sort of thing before, and don't want to break the boot that goes down to the plug.

It doesn't look like the fuel rail is in the way to remove the plugs, just the coils.

thanks!

 

[crash594]

Its easier to remove the fuel rail but not necessary. If you remove the fuel rail watch the orings. They fall off and you do not want to drop one in the cylinder. Do not use anti-seize (not needed on 4.6 only 5.4) and motorcraft plugs only. Do remove cold. Autolite plugs do not like all 4.6 engines (V6 yes). Make sure you use alot of dielectric grease on the spark plug boot (COPS or wires). The are not between the exhaust manifold. They are straight down on the top of the cylinder. You should have COP's (coil over plugs) mounted on top of the cylinder next to the fuel injectors. Just take your time.

 

[rumpledoll]

Interesting! Can you elaborate on why no anti-seize compound on the plugs for this engine? I though one should always use anti-seize on any engine when changing plugs - I didn't realize that there was another side to doing this procedure. Any insight appreciated.

Rumple

Do not use anti-seize (not needed on 4.6 only 5.4)

 

[crash594]

On the 5.4 engine it is a different style plug and is not used on the threads it is used to prevent build up on the peice that extends into the cylinder. Both engine have issues with the plugs backing out. Antiseize was used in the past with cast heads. Steel on steel and the would rust together. The new headr do not have that issue.