Spark plugs for a 4.6L Lincoln/Ford/Merc?

[69GTX]

With 78K miles on my 2002 Lincoln 4.6L dohc I'm starting to think about replacing the original plugs. Car still drives nice though with no codes or anything. One of the few things they did right on this engine was burying the plugs under protective covers and having pretty easy access. The 3v plugs of the 2000-2004 era seem to be problematic (2 piece, get stuck easy and/or break into pieces during removal such that it is recommended to get them out very early in life). The 4v plugs don't appear to have those issues. I did some reading on this last year and a bit more yesterday. The original Ford spec of AWSF-32EE or PP has been replaced a number of times (half thread, double plat, med electrode, stock heat range). Best I can come up with from Ford are Motorcraft SP439 or SP432 PPM...and those don't appear correct with full threads. When originally installed (to save $) they supposedly only coated one tip with platinum and pointed that side towards the combustion chamber. The specs for each bank of 4 were different on day 1. Today they aren't. The Autolite APP104 and Champion RS12PYP appear as proper replacements. The NGK numbers don't seem to be consistent. I'd probably feel more comfortable with Motorcraft plugs. So what's the best/proper plug to reinstall? I don't plan on ever doing it again. And I don't more than another 80K on the next set. Should I do them now or wait until 100K+ miles when something actually acts up? It does seem many people get 100K-125K miles on these. I suspect I should have some spare boots on hand if I rip them. Dielectric grease for outside, inside of boots. What about spark plug grommets? What about the age of the coil wires as it's pretty toasty warm up there in the summers? From what I read a rubber lined socket or magnetic one is helpful to get the plugs out of the deep wells. I'm leaning towards waiting to 100K. There must be some other 4.6L owners here who have gone well past 100K miles? And if you replaced them already, what did you use, how have they worked out?

 

[Panzerman]

I would wait. I changed my 2002 Lincoln Continental out at 75,000 miles and the plugs looked new. My company truck is a Ford F150 with 234,600 on it and still the original plugs and runs Great. They don't fix it until it breaks. My 2002 Lincoln did cough out a plug at around 120,000. Ford makes a kit and it was relatively painless to get it fixed. I think $125. Aluminum heads in there. I would just be weary. My 02 Lincoln was carefree until it hit about 110,000 then it was the worst car I ever owned. Between 110,000 and 160,000. I replaced the fuel pump/ coil packs/ air ride suspension/ water pump/ air conditioner compressor plus the transmission was on it's way out when I traded it. Believe me I am anal on maintenance still ran Great and used no oil.

 

[HemiHawk]

Changed my 4.6 3V plugs around 60k miles. They looked fine, but certainly noticed a bit more throttle response. Everything I read about it said go with the motorcraft plugs. I did that, only about $70 I think for the set.

 

[69GTX]

Originally Posted By: Panzerman

I would wait. I changed my 2002 Lincoln Continental out at 75,000 miles and the plugs looked new. My company truck is a Ford F150 with 234,600 on it and still the original plugs and runs Great. They don't fix it until it breaks. My 2002 Lincoln did cough out a plug at around 120,000. Ford makes a kit and it was relatively painless to get it fixed. I think $125. Aluminum heads in there. I would just be weary. My 02 Lincoln was carefree until it hit about 110,000 then it was the worst car I ever owned. Between 110,000 and 160,000. I replaced the fuel pump/ coil packs/ air ride suspension/ water pump/ air conditioner compressor plus the transmission was on it's way out when I traded it. Believe me I am anal on maintenance still ran Great and used no oil.

Thanks Panzerman. When your 2002 spit out a plug, does that cover contain the ejection? Is that 1 reason why they put those coil/plug covers on because of the weak half thread engagement? What's the symptom when that happens? Rough running, coughing, power drop? It must be pretty obvious. Can't wait for it to happen to me. My 1997 Lincoln was a great car until the 125K-150K mile mark. I started getting nickled and dimed on things like window motors, suspension parts, AC, radiator, etc. It never seemed to end. My biggest mistake was going from 175K-225K miles when it became pretty rusty on the under carriage. Doing a rear sway bar around 220K miles was money down the drain. And brake lines were rusting through about the 225K mile mark. My 2002 will never get that rusty though. It doesn't see daily commutes in the slushy New England snow. As a result the undercarriage is super clean despite being in New England all 16 years. My 1997 was junk at 12 years old. I spent 2 hours on Sunday with some Eastwood Corroless going over any surface rust on the undercarriage of the 2002. There wasn't that much...maybe a square foot total of little touch ups on the frame. Almost nothing on the floor pans. I don't intend to take this 2002 past the 125K-150K mile mark. And it might be best to unload it around 100K...or when the first 1 or 2 next big items pop up. So far, it's just been a radiator and one front axle (tone ring cracked on a pot hole). My 1997's transmission was working fine to the very end. It was the engine that had something go wrong at 232K miles when a metal squeal started around the water pump/alternator area. And that noise began the day I started the car up after it sat for 3 months from Jan-March. It turned out to be a Cam position sensor where just hitting it brought it back to life. Never did replace it. I was in the process of selling the car as a driveable "for short distances only" parts car ($350 ask). The new owner test drove it "hard" for 1/2 mile and it made it more noise. It was bad enough the brakes were leaking, the guy wanted to drive it home 45 miles. He got about 40 miles on I-95 when the engine overheated and seized up on him. Then it was really a parts car. What a poor death for my Dad's old car. A year earlier some guy offered me $600 for the car because they needed a door for a buddy's car. Had I known the car would become a boat anchor a year later I'd have surely said yes.

 

[69GTX]

Originally Posted By: HemiHawk

Changed my 4.6 3V plugs around 60k miles. They looked fine, but certainly noticed a bit more throttle response. Everything I read about it said go with the Motorcraft plugs. I did that, only about $70 I think for the set.

About half of what I've read said to go with Motorcraft to avoid problems or mis-matching something. The other 50% going with Autolite, NGK, and Champions in that order. Watch out for plug blow outs.

 

[blupupher]

Motorcraft SP433 should be the correct plug, but is still single platinum.

 

[slacktide_bitog]

For your 4V, get either NGK 7740 or Denso 5070. But if you want something to last well over 100k, consider iridium. In particular, NGK's Laser Iridium plugs are very good, and will last a long line (many even last 200k and still look good!). In fact, NGK Laser Iridium is OE on a large percentage of cars today. Most AC Delco and Motorcraft iridiums are in fact reboxed NGK Laser iridium. And of course, for transverse engines where access is impossible, then iridium is a must. For the 3V engine with the 2-piece spark plugs, Bosch will soon be making iridium plugs for it. Part number 96322. Not sure when they will be out, though. Made in Germany.

 

[Panzerman]

The cover contained the coil pack and plug but because of the heat melted the coil pack. It happened while my daughter was driving it. I drove it to the garage. Really bad miss, like a bad coil pack. What I thought it was till I took the cover off and the coil pack had the plug in it. Quick easy repair though thanks to Ford. My Lincoln was nice a shiny too for a car 15 years old. No rust underneath but I am Florida, cars last forever here still had the production stickers on it. The leather seats were starting to wear out on the drivers side. Nice car but if I didn't need a car for my daughter I would have gotten rid of it sooner. She bought the Ford from me so I traded it on the Challenger.

 

[bunnspecial]

I'd agree on the NGK 7740-it's what I used when I did the plugs on my dad's '01 Continental. Like others have said, his still looked almost new at 75K. He did the ones on his '98 at 125K, but mostly because it needed one or two coils. For goodness sake, though, it's a job you only want to do once. The front four are a walk in the park. The rear four are a nightmare.

 

[69GTX]

Thanks for those plug inputs and story. Looking at it again today I realize the angle of the rear plug bank won't be near as fun as the fronts. I'll take a look at those NGKs 7740 too. I wrote them down initially yesterday, then found another site that said NGK 6644 were correct. On a different note, I was going through a Lincoln blog where a guy had a thread on his refurbishing of his 1999 Lincoln Continental. Thought I might be able to get a few tips out of there. 1999 Lincoln thread One thing I picked up on was the air dam. It's been 7 years since I got my car. And my "air dam" is just a bottom cover now. There's no upward deflector remaining to push air up into the radiator area. It must be designed to do that as well as shield something on the undercarriage behind it. Mine has 2 of the 5 anchoring tabs gone as well. Maybe time to get a new air dam rather than the "air cover" I currently have. My 2002 doesn't have the quarter panel drain plugs that the 1999 has. I looked everywhere. No rust and no drain plugs. That must have been an improvement in the later model years. I never even looked for such things on my 1997 and it never had any obvious quarter panel rust as this guy's 1999 showed.

 

[slacktide_bitog]

Originally Posted By: 69GTX

Thanks for those plug inputs and story. Looking at it again today I realize the angle of the rear plug bank won't be near as fun as the fronts. I'll take a look at those NGKs 7740 too. I wrote them down initially yesterday, then found another site that said NGK 6644 were correct.

In that case, get iridium! For a transverse V6 or V8 where rear access is impossible, long-lasting iridium is a MUST! (And also, if you need to pull the intake, replace the valve cover gaskets) Get NGK part number is 97287. The 6044 was replaced by the 97287. 97287/6044 is iridium 7740 is platinum Replace your spark plugs with NGK Laser Iridium, and you'll never have to do them again!

 

[69GTX]

I'm with you Slack_bitog. I only want to change plugs once. I can only recall one car where I changed them twice....that 1988 Crown Vic went 212K miles before the transmission went out. One of the better cars I've ever owned.

 

[Colt45ws]

I like to use Motorcraft SP500. Finewire platinium one step colder than stock. If you dont have a socket that holds the plug, a piece of fuel line or similar the right size can help. Just push it on. Also, if you have a air compressor, get a long blowgun to blow the [censored] out of the plug holes. I dont know about you but I dont want that grime falling in my engine. My blow gun had 1/8NPT threads for the nozzle, so a trip to home depot and a long 1/8 nipple fixed it.