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Installing New Spark Plugs in 3.8 JK

Discussion in 'Wrangler JK (2007-2017)' started by Justanotherjeeper, Jan 15, 2021.

  1. Jan 15, 2021 at 9:04 AM
    #1
    Justanotherjeeper

    Justanotherjeeper [OP] Well-Known Member

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    Hi; my winter covid project is a 2011 2 door JK that I purchased last November. It sits on jack stands in the garage, and has been a great diversion from the troubled times that we find ourselves in.
    My Jeep has 75K Km and wasn't due for a plug change according to the manufacturers recommended maintenance schedule, but I thought that since it was sitting there and receiving a full service along with some other rebuilds, I may as well change the plugs too. Unfortunately, the arise of modern engines has made changing spark plugs almost an anachronism, denying the home mechanic one of the formerly, simplest of pleasures, lol. Spark plugs are mostly inaccessible on most vehicles, however on the 3.8 Pentastar, they're quite easy to change. I'm a pretty slow and careful mechanic and I did it in 1 1/2 hours, so I'd give it a "1" on a 5 scale of difficulty. The dealer charges a lot for this service, but the average person can easily do it. I'm posting this because when I looked this procedure up on You Tube there are guys there removing the passenger side inner fender, battery box, fuse box - you name it to to gain access to dreaded spark plug #5, lol. Hey, this is unnecessary, which I'll get to.
    1. Some change plug wires at the same time, but mine were good, so I left them for the time being. Give the boots a turn to free them from the plug, and pull them off with a good grip on the boot itself, not the plug wire. You'll hear it unsnap when it comes free.
    1. As I found, all of the plugs on a 3.8 Jeep Jk can be accessed with simple tools and removed with patience and care. It's a good idea to blow out the plug recesses with compressed air to make sure no dirt or debris falls in there when they are removed. Don't be intimidated by the passenger side of the engine. Move the heater hoses out of the way, and you can access the plugs. The drivers side plug bank is visible and simple to remove.
    2. I like to lay out the plugs I remove and check them for evidence of engine problems. In this case, the plugs exhibit normal wear and tear for something 10 years old with 75K Km. The electrodes are worn, with a gap of .060 instead of .050, but other than that there are no issues here.
    jeep spark plugs.jpg
    3. The new plugs I used are OEM replacements - Champion RE14PLP5.
    4. Check the gaps on the new plugs - they need to be .050
    5. Reinstall the new plugs by hand to insure you do not inadvertently cross thread them, and that they turn easily going in. The manufacturer suggests using a small amount of anti seize on the upper threads, but I didn't do this. The use of anti seize can encourage over tightening and plugs should never be installed much beyond snug. 12 ft/lbs is recommended, which is about an 1/8th of a turn past hand tight.
    6. Put some dialectric grease or vaseline on the inside of the boot so they will slip on easier, using a Q tip. Don't overdo it. A little is all you need.
    7. Start up the engine and enjoy the sound of a smooth steady engine fire, knowing everything is good for the next 75K km!
     
    Last edited: Jan 15, 2021
  2. Jan 15, 2021 at 10:11 AM
    #2
    Justanotherjeeper

    Justanotherjeeper [OP] Well-Known Member

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    paid cash for it.
    I just saw this photo - of a new bronco chassis with engine. I’m not sure where the spark plugs are on this engine, or how much it would cost to change them, lol! In fairness, it looks like this chassis was on its way to the dyno shop for some testing, so maybe the production version will have less hoses! It looks like I need to keep my 2011 going for a long time in order to avoid more modern vehicles like the new bronco as much as possible. Maybe I can hold on long enough for a fully electric Jeep and avoid ICE vehicles completely going forward.

    F2C30764-B5BB-4551-8C32-2DD1D7FCDBA2.jpg
     
    Last edited: Jan 15, 2021
    skyhookman, LYFZGOOD and aggrex like this.
  3. Jan 15, 2021 at 10:15 AM
    #3
    aggrex

    aggrex Well-Known Member

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    That's ridiculous! As technology improves the number of hoses, sensors, computers and nanny devices etc just gets bigger and bigger. What ever happened to K.I.S.S.
     
  4. Jan 16, 2021 at 4:21 PM
    #4
    JKBob 25

    JKBob 25 Well-Known Member

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    It's been awhile since I posted up anything here. Didn't miss none of you guys. LMFAO.

    I just replaced my plugs and coil packs in my 2016 JK. Unfortunately, it's nothing like yours @Justanotherjeeper. I did however watch several Utubes on this ordeal. Being slow and meticulous. Took me almost 4 hours. If you've ever changed the plugs on 2012 and new Pentastar 3.6 motor. You know what I'm talking about. I liked this guys video.

    https://youtu.be/bPHiY-X5f8g
     
  5. Jan 16, 2021 at 4:29 PM
    #5
    aggrex

    aggrex Well-Known Member

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    Mines also a 2016 JK @26K so what triggered you to change the coil packs and plugs?
     
    JKBob 25 likes this.
  6. Jan 16, 2021 at 7:45 PM
    #6
    Justanotherjeeper

    Justanotherjeeper [OP] Well-Known Member

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    Good on you @JKBob 25! I happened to watch a couple of 3.6 videos while getting ready to work on my 3.8 and I was happy I didn’t have to do that! Lol.
    But the reward comes at the end.
     
    aggrex and JKBob 25 like this.
  7. Jan 16, 2021 at 9:15 PM
    #7
    JKBob 25

    JKBob 25 Well-Known Member

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    20210114_141256_HDR.jpg
    Manual suggested to change plugs at 100k. I was at 107k. I saw mpg's getting worse. Acceleration dropping as well. And my Carfaxx was unclear as to some of my JKs mileage maintenance and what not. Sooo. Also...I found mud in places I shouldn't have in certain places I didn't expect. But it was a lender and rental Jeep before I found it at a local dealership. That being said.
    Either way. Magilla was due for a plug swap. And based on research. I figured since I'm going to that extreme. Id swap out coil packs also too. I went with Accel ignition coils. There are several others. MSD..RIPP.... Always been a fan of their products since my Chevy V-8 days. So I went with Accel.
    As of now. 3 days. A noticable difference in acceleration right off the bat pulling out my driveway. MPGs....I went from 15 or so to 17 around town. Still not sure on highway mpgs. But I will report back.
    For the labor it takes to replace your plugs. Do some research. And upgrade other Mopar parts that you can. Oh yeah...also replaced intake manifold gaskets.
    If you haven't removed your intake manifold. Your in for a bunch of fun. No...And I mean. NO....video was exactly like what I encountered.
     
    Last edited: Jan 16, 2021
  8. Jan 16, 2021 at 9:22 PM
    #8
    JKBob 25

    JKBob 25 Well-Known Member

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    So you saw what was involved on the 3.6 Pentastar intake removal? I'm telling ya. I watched several videos. And none...NONE....forewarned me what I was about to undertake.
    But ya know what. I was happy I did it. Was a learning experience. Next time.....3 hours.....
    Also...I would suggest some dielectric grease in the coil pack boots. Just alil. Will help in your next plug swap...
     
    Last edited: Jan 16, 2021
  9. Jan 17, 2021 at 6:59 AM
    #9
    Justanotherjeeper

    Justanotherjeeper [OP] Well-Known Member

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    My son in law has a 2018 JKU, and I’m sure I’ll get to try this out when his time comes, @JKBob 25 ! Challenges like this are always fulfilling in the end, right? In the meantime, I now appreciate my old 3.8 a little more, lol. I haven’t noticed any change to my Jeep with new plugs. It ran great before and it runs great now. In my case, I could have probably gotten a couple of years more out of the old plugs, but maybe not. The mileage was low, but at 10 years, it’s time had come, I figured. I have a friend who is a local mechanic who had to change a pentastar engine in an older Chrysler sedan, after someone didn’t change the plugs and they got so hot and worn out that a piece of ceramic cracked and fell off the tip of one into the cylinder and scored it up pretty badly. So bad things can happen to machines if they don’t get preventative maintenance!
     
    Last edited: Jan 17, 2021
  10. Jan 18, 2021 at 4:07 PM
    #10
    JKBob 25

    JKBob 25 Well-Known Member

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    So true @Justanotherjeeper . When I put everything back together and I turned the key and it started right up. I was like....YEEESSSSSSS. I don't doubt my mechanical ability. But there's so many things that could go wrong, or forget to reconnect. Not to mention if your get any crap in any of the 6 intake holes or as you mentioned. If a plug breaks up.

    But Im also a true believer in preventive maintenance.
     
  11. Jan 18, 2021 at 6:12 PM
    #11
    aggrex

    aggrex Well-Known Member

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    Was that blue painters tape covering the open engine? That's a neat idea.
     
  12. Jan 19, 2021 at 3:38 PM
    #12
    JKBob 25

    JKBob 25 Well-Known Member

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    20210114_141242_HDR.jpg Yup @aggrex . I cant take credit for the idea. I did see it in another video. I also have always used it to wrap the negitive battery cable any time I remove it to work on something.
    You can see it here on the upper right.
     

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