Home Forums Gear Hunting Trucks and Four-Wheel Drives Changing spark plugs in Ford F150 4.6 litre

I have a 2003 with 108,000 miles with the original spark plugs. It sounds fine and runs great.
I have heard horror stories about changing plugs. Is that the 5.4?

4.6 and 5.4 are both in the same engine family (modular). Doubt there is much difference in the mechanics of a plug change.

The three valve 5.4 is the one that you hear the "horror" stories about. Best to have a 7mm 1/4 drive swivel socket to remove coils, compressed air to blow away debris before you do, and an assortment of different length extensions for your spark plug socket. If it calls for Iridium plugs, get them. Use Motorcraft OE's also. No Bosch, Autolite, Champions, or whatever fad spark plug they have on special. Antiseize and gap them. Put them in tighter than you would ANY other plug in an aluminum head, they have a bad reputation for backing out about twenty thousand miles or less down the road. Pulls threads, breaks coils, cost money.

Most newer aluminum head cars requires retorque of plugs. My wifes Honda Odyssee plug was loose after about 7 K after plug change. Caught it just in time.

Sounds like something to pay Ford to do...

Why?

If you have the plugs like I do, there is no gapping them. If you follow directions, change the plugs on a COLD engine. Pull the C.O.P. blow out the debris, crack them loose 1/4 turn and soak them with penetrating oil and let them soak for an hour.

Luckily I didnt break any when changing them on the wifes truck. Although I did buy the extraction tool just in case.

Yeah, that is the three valve 5.4 style. About every third motor one of those break. Not so bad if it's one of the front cylinders, but luck doesn't always work that way! New plugs are redesigned so that tip is a one piece construction, but that is of no help getting out originals. A wet soak with Seafoam or similar can be helpful too.

I would caution against that, there's some heads out there that are short threaded and you REALLY don't want to strip them out. Read up on blown plugs and these motors.

Blown plugs are why you put them in tight. I'm not talking cheater bars here, just tight. I've only done eighty to a hundred vehicles worth of these things. Never stripped one out putting it in, but have done thirty or so plus sleeves because some one else or the factory didn't put enough oompa on them when they went in. Never used a torque wrench, but I think twenty to twenty five pounds is about all we're talking here.


PS, have always liked your avatar.

Changed the plugs today with 108,000 they looked like new.
My mechanic did it for me in 2 hrs.