HOW TO: Change Spark-Plugs

Discussion in 'How To' started by JeepJeepster, Dec 14, 2007.

  1. JeepJeepster

    JeepJeepster Full Access Member

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    This was alittle more involved than I thought it was going to be. For one thing, having a lifted Jeep with bigger tires makes it a pain in the rear to work on anything in the engine bay. This was the first time working on it with the new tires on it and I can tell a big difference.

    Three on each side as I sure everyone knows. The three on the drivers side was pretty much a snap. I used a 6in extension on the 5/8 sparkplug socket and a 3in on top of that.

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    Pop these little guys off first by grasping the base of them and pulling straight up. They are on there kinda good but there is only two of them. Both are on the Drivers side.

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    The coil takes a 10mm socket. Pull straight up and they just pop out. BE SURE you use compressed air to blow any sand and crap out from around the spark plug before you take the plug out. It was amazing how much crap I blew out once I took the coil out.

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    Plugs didnt seem to be in bad shape at all other than being gapped way to much. They were rusted to heck thanks to me detailing the engine to much. :D

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    New plugs. I got some Autolite Double Platinum's. I forgot to check the gap on the first two, but the other 4 seemed to be right at .040 which is what the 3.7 calls for.

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    I cleaned the seals up on the coil and put some Dielectric grease all over the seal, outside of the boot, and inside of the boot. I also put Anti-seize on the spark plug threads along with some Di-electric grease on the plugs ceramic. If you dont do this, the socket will get stuck on the new plug once you tighten it back into the head. Good luck with getting that socket back out if you forget to put grease on the plug as its deep in the engine.

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    I had to use two 6" extensions along with the 3" on the passengers side. The front two were not that bad, but watch the dip-stick on the middle one, I can see someone breaking the yellow handle off of it or bending the tube.

    The back plug needed a swivel joint and my joint was lacking in performance. I did not need to take the coolant tank off but it would give you more room. I suggest picking up a good swivel with a ball joint in it and not a ujoint type. I was worried I was going to break the plug off as its hard to hold the socket on straight and turn the ratchet at the same time. Its best to have someone hold the other extensions on the socket while you turn the ratchet. This is what I used:

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    here is the type Im talking about:

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    This is what I used:

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    Take care not to over tighten either the spark plug or the nut on the coil. The coil doesnt need much at all as its plastic. Im not sure what the torque value is on the spark plug, I just tighten it till I feel the washer bottom out.

    Take your time and dont rush through something like this. It ended up taking me around 1-1.5hours but I was just doing it at my own pace. No use in getting in a hurry with something like this and screwing something up. Take care around all the vacuum hoses and such too. There is a ton of them and it would be easy to break one of them off.

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    Ohh, and watch the seals in the plugs that connect to the coils when you take them off. I had one fall out and it just happened to fall in my hand when I took the plug off of the coil. It got dark on me when I was done, but Im going to pop all the of the plugs back off and check all of them to make sure none of the others fell out before I start it up or drive it.

    Edit: One thing I want to add, make sure you thread the plugs in by hand before tightening them down. This way you can make sure nothing gets cross threaded before you torque them down.. :)
     
    Last edited: Apr 1, 2008
  2. tommudd

    tommudd Moderator Staff Member Moderator

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    man those plugs look nasty, is this the first time changing them out? I think Ive done mine 4 times now....oh thats right yours is low miles...... LOL good write up
     
  3. JeepJeepster

    JeepJeepster Full Access Member

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    4 times?! How many miles do you have on your Jeep?!

    I turned over 30k yesterday. :)

    List of things I wanted to do at 30k:
    -Spark plugs
    -Tcase
    -Tranny
    -Engine oil+filter
    -Power steering fluid
    -Maybe the PCV valve..

    I went ahead and did the tranny and tcase back in the summer when it was warm. Got the spark plugs done now so all thats left is the engine oil and power steering. They are giving rain all day tomorrow. :(
     
  4. Ry' N Jen

    Ry' N Jen Banned

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    Excellent write up Blake.
    Won't bee till next spring that I am going to inspect/change mine.

    Cheers
    Ryan
     
  5. desertkj

    desertkj Full Access Member

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    Those plugs were in horrible shape. I'd say you should get a little more performance out of it with new ones. However, I don't remember changing the sparks plugs on mine being that high of maintenance. We've done it twice now ourselves.
     
  6. Dave

    Dave Administrator Administrator Moderator

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    Really a nice write up Blake.

    I will be doing mine in the spring along with the t-case and diff's. I never did a plug change before that had the coil packs on top like the KJ. So I was concerned about breaking one of them. Looks like the electrodes wore down some. And this was at 30,000 miles. I am at 27,000 so I'm due also.

    Does it seem to run smoother? Are you getting better gas mileage?? Let us know.

    Dave
     
  7. JeepJeepster

    JeepJeepster Full Access Member

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    Im going to wait till daylight tomorrow before starting it to check all of the plugs on the coils after that seal fell out of the one plug. It got dark on me and I couldnt see anything, but it ran fairly smooth before so I probably wont notice a difference. I wont get a good reading on the mpg till I got back to school which will be after christmas. I live in a small town so the mpg is always 16-17 around here.

    Just make sure you blow out around the plugs first before taking them out. Even if you dont have a compressor, a can of compressed air will be better than nothing.
     
  8. hyde

    hyde Moderator KJ Supporting Member

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    Great timing Blake, and nice pictures.. Thanks.
     
  9. Dave

    Dave Administrator Administrator Moderator

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    This needs to be a "sticky"..................Someone sling this up against the board and make it stuck....Mods???

    Dave
     
  10. 2003KJ

    2003KJ Member

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    well I stucked it....but then I thought, this really should be over in the how to section, so I unstucked it, and moved it over :D

    Nice write up dude. And I did mine at 25K (just clicked 50 last week, so i'm about due for another one) and they looked that bad....at only 25K!!!

    And atleast you didn't do what I did, which was snap the dipstick handle clean off trying to get that last plug on the passenger side out.
     
  11. JeepJeepster

    JeepJeepster Full Access Member

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    I made a comment on that. :)
     
  12. jeepkj02

    jeepkj02 Full Access Member

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    I did that on my brothers 4.0L WJ when I changed the plugs. PITA trying to get the tube out to get the dipstick out.

    I used the same plugs on my KJ, so far so good.
     
  13. 2003KJ

    2003KJ Member

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    LOL yeah. I ended up having to get a whole new stick from the dealer (like $15....expensive little bugger) and drill the old one out. Nice to know i'm not the only one who's done that before...LOL :D
     
  14. Marlon_JB2

    Marlon_JB2 Kombat Edition Jeep

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    Ouch. Those looked horrible. You should have changed the stock NGKs out at 20k like some of the rest of us did.... 30k is too long for those.
     
  15. tommudd

    tommudd Moderator Staff Member Moderator

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    Blake; (Jeepster) mines an 04 with 94000 and change them every 24/25000 miles, I do everything more often than needed but then I always have a list of people who want my old vehicles when I get tired of them in 175/200,000 miles LOL Nice write up!!!!!by the way
     
  16. Arizona KJ Carlos

    Arizona KJ Carlos Full Access Member

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    Thanks for this post. I just finished doing my spark plug change and this posting helped a lot. For the driver side I didnt have any issues, but for the passanger side, I would recomend removing the coolant reservoir by taking out the nuts without disconecting the hoses. I also had enough cable left in the back spark plug to be able to take out the coil with out disconecting the electrical connector. Great posting!
     
  17. AbsoluteRenegade

    AbsoluteRenegade Full Access Member

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    I did mine as well, with the extensions and the joint. I would like to add that using a little antiseize compound works great, and really gooping up dielectric greeze around the socket area kept the plugs in the socket while putting them in. If you pickup one of those little flexible 18inch "grabbers" it will help you pull the plugs out if they arent sticking in the socket. you know those little grabbers, handy if you drop a nut in the engine bay as well.....ha ha. Changing plugs on my frankenlifted jeep with 245s was a real PITA. In my hardbody I usually take the tires off and drop it down on blocks, almost like working on an MG then!
     
  18. BorisMD

    BorisMD New Member

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    I just did my plugs for the first time (at 78K), and they were in pretty worn out shape. Not bad in terms of residue, etc.

    I, too, agree with removing the coolant tank (but leaving the hoses attached). That made access to the rear plug much easier.

    There was a mouse nest under the air box just in front of the air intake opening. I removed that. Fortunately, they hadn't chewed up anything.

    Thanks for the great write up.

    Regards,

    Boris
     
  19. tjkj2002

    tjkj2002 Full Access Member

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    Hey jeepjeepster,

    I just noticed in the pics on the first page those are just thr regular Autolite platinums and not the double platinums.Just thought you should know.
     
  20. indieaz

    indieaz Full Access Member

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    ^ I didn't bother removing my coolant box, that would have been a pain. I connected a 12" extension to a swivel attachment, then another 12" atachment and got plug #6 out that way.