I've searched and found many posts with varying advice on the troublesome coil-over-plug problem. I've replaced COP's 6 times on my '03 SCrew since the first one went bad in 2010 with 91k on it.

Replaced #1 and #4 within a week of each other, then #3 nine months later and # 5 seven months after that. Went with Duralast from AZone, which carried a 2 year warranty.

I have now had to replace the replacements twice, having failed in the order they were replaced (#1 and #4). Most recent was with 31 months and 34k miles on it. I was able to do #4 in about 15 minutes, but I don't like the fact that I've gotten good at it through practice...

What's the word, folks? Does Motorcraft have it figured out? I'd be interested in feedback from someone who's gotten more than 50k out of a COP on this model year range vehicle.

Thanks!

Bryan

 

Bryon, i've had extensive experience with the COP issues in an 02.
Tried other vendor sources but found the OEM is the standard for reliability.
Make no mistake, these items are considered maintaince items even through we think they should have nearly endless life like the old single coils had.
One problem I see is the coils set on the heads and with the cooling fan adding heat to them plus the heads, they take a beating from all the heat.
When you turn off the motor the heat from the exhaust manifolds rise plus the temperature in the engine bay rises quite high for nearly 10 minutes before beginning to drop.
As part of the transmission cooling, I have an electric fan cooled transmission cooler that is thermostatically controlled to run above about 195 so when the engine is shut down the fan runs to vent the engine bay limiting the temperature as well as help cooling the trans fluid at low road speeds while towing.
After sorting coil issues and going back to OEM units and using installing the fan the fail rate seems to have dropped to zero and now with nearly 178,000 miles.
I feel that limiting the engine bay temperature has had a positive effect on coil life but can't positivly prove it plus using the OEM coils.
You seem to have poor life from your coils so thought you might get something from my comments.
Use OEM coils and maybe consider just a small 8" electric fan in front of the radiator to run after shutdown controlled by an adjustable thermostst that is powered through a fuse full time so it will be automatic.
After shut down depending on the outside temperature, the fan will run about 5 minutes to 8 minutes in ambient temps above 90 + degrees and vent the engine bay limiting the temperature and extending rubber parts and hopefully coil life .
Good luck.

 

Original COPS replaced at 135K miles. I now have 235K miles and have also replaced a dozen aftermarket COPS in the last 100k miles .. I bought them on e-bay for $100.00 for ALL 8,....factory units are much higher. ... Some of the aftermarket lasted 50K, a few have 100K now.

 

Have started changing out my plugs. These are originals with 125k on them. Not too bad looking to me, but wondered what others thought. They're the #1 thru #4 (left to right). #2 looks a bit different, and was noticeably easier to unscrew from the cylinder. Took almost no torque on the wrench to break loose, almost like it had been replaced and only hand tightened. Anyway, this is such a PITA that I'm having to do a few at a time. Did one last night, then 3 tonight. Will try to tackle the driver's side later in the week. From the looks of it, I'm gonna need a lot of patience. This is a 4.6L ... not sure what they were thinking when they designed the spark plug buried so deep in the engine. Never had to do a blind removal and re-install on plugs before. Felt like a little leap of faith on #4... it's so far under there, I was afraid of dropping and never recovering it. Anyway, just wanted opinions on how these look. Thanks.

 

The second one was leaking combustion past the threads and tapered seal from being loose.
The deposits are hydro carbon products of combustion.