2003 4.0 Spark Plugs

[03Explo20]

Planning to change the plugs and wires in my 2003 4.0. Was wondering if anyone had any tips? It appears those back plugs are a chore to remove. If I took off the tire on each side, can I reach the plug with a extension? Would it hurt any if I hit the plugs with some PB Blaster prior to doing the work? There is quite a bit of rust around the area so I'm guessing the plugs will be in there rather tight!

 

[Littleant]

Cannot speak on your 2003 but on my 2010 Mountaineer I blew out the plug holes of any debris first.

Then I sprayed PB blaster down each plug and let it set for an hour. Plugs were tight but did come out fairly easy.

I loosened them one at a time then tighten them working them back and fourth.

MOST IMPORTANT ENGINE MUST BE COLD.

 

[TechGuru]

Mine were a easy change. Previous changer (Ford Service) used anti-seize on the threads. Rust should not be a issue, heads are aluminum and the proper SP500 Motorcraft are chrome plated.

I used a torque wrench when installing the new ones. (13ft-lb)

 

[wilpetty]

The back bolts are not difficult on either side...the front driver side bolt will need you to use a short extension, and the rest you can use a medium/long extension

 

[03Explo20]

Guys, I was able to change out the plugs today without much of a problem. My new set of wires I ordered has a bad wire within and I had to use one of the old wires so I'm hoping the seller on eBay can at least exchange the one wire. It looks as if the wire is missing the snap ring inside and won't clip on to the plug.

Also, the rear most plug on the drivers side was in hand tight! I was able to spin it out without using a ratchet! I noticed, though, that on one side of the motor (drivers side), the plug tips were worn way down compared to the other side. I thought that to be a bit weird. Any ideas why?

I did also mix up two wires for the front two drivers side plugs and when I started the truck it was running rough and was hard to crank over. I switched the wires on the coil pack and it runs great now!

In case I get nothing from this eBay seller on the bad wire. Is there a universal plug wire I can buy to put on or am I going to need to buy a whole new set of Motorcraft wires just for the one I need?

 

[TechGuru]

Guys, I was able to change out the plugs today without much of a problem. My new set of wires I ordered has a bad wire within and I had to use one of the old wires so I'm hoping the seller on eBay can at least exchange the one wire. It looks as if the wire is missing the snap ring inside and won't clip on to the plug.

Never buy parts that affect drivability off of ebay. Only part I ever got off ebay was a A/C compressor from a salvage yard for like $60.

Also, the rear most plug on the drivers side was in hand tight! I was able to spin it out without using a ratchet! I noticed, though, that on one side of the motor (drivers side), the plug tips were worn way down compared to the other side. I thought that to be a bit weird. Any ideas why?

It's the wasted spark ignition system these vehicles have. The two sides have the electricity flowing in opposite directions of each other.

The wasted spark system is an ignition system used in some four-stroke cycle internal combustion engines. In a wasted spark system, the spark plugs fire in pairs, with one plug in a cylinder on its compression stroke and the other plug in a cylinder on its exhaust stroke. The extra spark during the exhaust stroke has no effect and is thus "wasted". This design halves the number of components necessary in a typical ignition system, while the extra spark, against much reduced dielectric resistance, barely impacts the lifespan of modern ignition components. In a typical engine, it requires only about 2–3 kV to fire the cylinder on its exhaust stroke. The remaining coil energy is available to fire the spark plug in the cylinder on its compression stroke (typically about 8 to 12 kV).

Wasted spark system - Wikipedia

en.wikipedia.org

In case I get nothing from this eBay seller on the bad wire. Is there a universal plug wire I can buy to put on or am I going to need to buy a whole new set of Motorcraft wires just for the one I need?

I'd get a whole set of Motorcraft, NGK, Denso, or Bosch anyway.