I went through my first COP job last week, and thought I would share some observations and pictures. I bought this ’04 base in the first week of January, and up until a few weeks ago it had run fine. I was familiar with the COP problems as I had owned two Lincoln LS years ago. In fact I joined this forum to find out how the COP problem was being addressed post-warranty, and found a lot of helpful advice here that encouraged my decision to purchase the car.
A few weeks ago I encountered some serious misfiring and flashing
check engine light, so I ordered up the
Parts Galaxy COPs and a new set of
NGK plugs (7994). Several previous posts gave some helpful instructions, but they notably used the passenger side for demonstration. “Look how easy!” LOL All told, it took me about 90 minutes to replace the
plugs and COPs on the passenger side. Might’ve gone quicker if I wasn’t doing laundry at the same time.
As others have noted, I found the
new COPs have a higher profile, and as such the plastic cover would not fit back down squarely. The net difference in height appears to be about 1/8”. Here are the two side-by-side.
By alternately tightening the six cover screws a little at a time, the cover went back down fairly snug but I doubt it would be water-tight. I ended up pulling it off again and applying a bead of
Permatex Black to improve the seal.
Here’s a tip a friend showed me. No rocket-science here, but he told me I would save time to tape the
spark plug socket to the extension. Once the new plug is in place and tight, it’s really easy for the extension to separate and leave the socket stuck on the plug.
I also found something I had never seen before. A couple of the old plug tips were a bright, oxide red color. A little Google research showed the most common reason for this is the use of an octane booster or intake cleaner added to the gas. Guilty as charged.
With the passenger side done, I moved over to the port side. And this is where the fun began. Lots more stuff in the way there. Despite this, I was able to get five of the cover screws out with little difficulty. I had to move the
power steering reservoir to the side slightly, and it was necessary to push the dipstick tube aside a little. Also removed the fuel vapor solenoid from the top of the strut, and disconnected the fuel line at the engine and pulled it back out of the way.
The bottom screw all the way back closest to the firewall was the challenge. I was able to get a socket on it, but it’s so close to the
brake booster there was no way to get a ratchet on.
So I ended up using a
7mm ignition wrench to remove it, and it took about 20 minutes making small-increment turns. I couldn’t find a
7mm gear wrench.
With the cover finally loose I began to withdraw it. That’s when the nightmare appeared. As another poster mentioned, these covers can keep water out, but they can also serve to trap water in. There was enough water under that cover to start a koi pond.
The entire recessed area under the cover was
rust-stained; water all down in the plug wells; and there was condensation all over the packs and wiring. This set of packs also looked different. These had no writing on top, where all of the ones on the passenger side had numbers and codes stamped on them. Probably replaced sometime in the past.
The car was only out in the rain a couple times, and through the car wash a couple times. The wiper seal had been replaced previously, and I had seen no signs of leakage around it. When I bought the car the engine was extremely clean, so it’s possible it was pressure washed. Who knows where the water came from. I may replace the wiper seal again just the same.
So I went about a very methodical cleaning process. First, I used paper towels to sop out as much water as possible from the wells, and then allowed everything to air-dry for a day or so. I left the old
plugs in to keep any debris from falling into the cylinders, and cleaned up as much of the
rust coating as possible. All of the screw heads were rusted, which is probably where most of the color came from. I carefully treated all of the screws and bolt heads with an
OSPHO-type cleaner to retard the
rust.
Once the outer area was clean, I used compressed air to blow debris out of the wells. A shop vac was helpful too. The hexes on the
plugs were heavily rusted, so when I began to remove the
plugs I stopped every few turns and kept blowing out debris before finally removing the
plugs and exposing the cylinder.
Next I applied some
dielectric grease deep down in the wells and on the plug seats. Then came the new
plugs, and the new coils. The coil wire connectors have a watertight seal, so there was no sign of moisture or corrosion in those connections.
Everything came back together well, and the engine is running smoothly again.
The last
part of the project was to get the coil cover back on. Like the passenger side I added a generous bead of
Permatex Black around the entire perimeter of the cover, as well as the channel where the coil wires exit in the rear. While I have no illusions, hopefully this extra step will keep water out in the future.
Something else I observed: both of these coil covers had a date stamp inside of ’07. The TSB that covered this issue (TSB 05-16-2) provided new coil covers, so it would seem a prior owner took advantage of the TSB.
It may not always be possible, but if you’re considering buying one of these cars it would certainly be worthwhile to pop these covers off and have a look for any surprises. I don’t know if I would have walked away from this one had I discovered this mess before buying it, but it certainly would have affected my offering price.
I’m grateful for all the helpful hints and suggestions from previous posters, and hopefully my observations above will serve to help someone else along the way.
