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SixZeroFour 11-25-2012 07:29 PM

DIY: Hemi 5.7L Spark Plug Change
Time for the dreaded 16 plug change? Here are a few tips and pictures to get you going... This is not that difficult of a job if you have the right tools and patience.

Notes: This swap should only be performed on a cold engine so plan ahead and do it first thing in the morning or on a weekend. Also make sure to set the gaps on the spark plugs correctly as they are not going to be pre-gapped in the package (OM lists 0.043 in gap). I would also strongly suggest doing the complete engine side at a time as you will save yourself a lot of time in not having to switch tools etc doing it a coil at a time.

Tools and parts required:
- 16 Spark Plugs.
Owners Manual: LZFR5C11G (Gap 0.043 in [1.09 mm])
Mopar Part Number: SPLZFRC11
- Spark Plug Gap tool
- 3/8 Drive Ratchet
- 3" Long 3/8 Drive Extension
- 3/8 Drive Universal Joint
- 3/8 Drive Torque Wrench
- 5/8 Spark Plug Socket
- 1/4 Drive Ratchet
- 10mm Short socket (1/4 drive)
- 10mm deep socket (1/4 drive)

Here we go...

(1) Remove the engine cover by pulling up firmly at the front edge with both hands and then repeat at the back of the cover.

You will now be looking at the top of the engine and will be able to see the tops of the coil packs down each side of the motor.

(2) Do your best to clean the area around the coil packs to prevent any debris from falling in while changing the plugs. Next unclip each of the 4 wire connectors attached to the coil packs (you can see I have removed the first one in the picture).

(3) Remove the Coil Packs - Start on the passenger side as it is more easily accessed and will get you ready for the more difficult driver side. Using a 1/4" Drive ratchet with a 10mm extension only crack and slightly loosen all 8 of the 10MM Hex bolts show above. Once they have been cracked you should be able to spin them the rest of the way using just your fingers. These bolts do not need to be completely removed in order to take out the coil packs so only loosen them about half way and the coil pack will come free. While removed I kept the coil packs in the correct order so they all went back in the same cyl they came out of. I dont believe this is necissary but did it anyways.

Here is a shot of the first coil pack once removed. The arms are flexible to make them easier to install/remove in the small space:

(3) Once all coil packs have been removed you can now crack all the spark plugs. I found that a 3/8 Drive ratchet with a 3" long extension, then a universal joint, then the spark plug socket was just the right length to be able to get to all 16 plugs without having to change extension configuration. (See first pic) Once they are cracked I found it fastest to remove the ratchet and loosen them the rest of the way by spinning the extension and socket by hand. If you have a good spark plug socket with a magnet you can skip the next step...

(4) I had a crappy spark plug socket with rubber boot that comes out every time so I used a telescoping magnetic tool to grab the old plugs and pull them out from the deep:

*Some people prefer to apply dielectric grease to parts of the plug and wire connection but there was plenty still left on there so I didnt bother. (btw I was quoted $35 for a new tube at the dealer :eek:)

(5) Using the spark plug socket insert the newly gapped plugs and thread them in carefully by hand to avoid stripping. Once all 8 plugs are installed finger tight use a torque wrench set at 12-14 ft/lbs to properly snug each of the plugs down. DO NOT EXCEED 14 lbs.

(6) Reinstall each of the 4 coil packs and pressing the stems down onto the plugs. Next go back to your 1/4" ratchet and 10mm socket to tighten all of the 10mm Hex bolts until the coils are snug and secure back in place.

(7) Re-attach each of the 4 wire harness clips

(8) Repeat steps 1-7 for the driver side. It is a little tighter to work with because of the intake hardware etc in the way but overall everything is pretty easy to access and the proceedure is the same as the passenger side.

(9) Reinstall engine cover

(9) Finally I disconnected the negative battery terminal for 5min to reset the ecu/tcu etc. This is also not required but I felt it was worth the minimal effort.

and that's it!... Fire it up and make sure everything is nice and smooth!

Impressions: I'm not going to lie, I was not impressed about having to change 16 plugs after 30k but am glad I did. I had recently been noticing a rougher than normal idle in the morning and at some stop lights but that is completely gone with the install of the new plugs. Also the engine without a doubt feels more responsive and has restored that like new power again.

Save your hard earned $$$ and DIY:thumbsup:


Scottina06 11-25-2012 08:33 PM

Re: DIY: Hemi 5.7L Spark Plug Change

ernestd 11-25-2012 08:59 PM

Re: DIY: Hemi 5.7L Spark Plug Change
Nice work!

moosehead 11-26-2012 09:58 AM

Re: DIY: Hemi 5.7L Spark Plug Change
Wazzup 604? You got any snow up there yet? We do not. Rode a mountain bike in short sleeves yesterday. Not good.

Nice work as always on the plugs DIY.

SixZeroFour 11-26-2012 10:39 AM

Re: DIY: Hemi 5.7L Spark Plug Change
Hey Moose - No snow here yet either except for a few dustings on the local mountains. It's been pretty mild similar to what it sounds like you are seeing in CO although we did finally get a good thick layer of frost on the ground this morning. Wish it would show up already as I've been dying to test out my silent armours in the white stuff... Any new mods to the beast?

Xjrguy 11-28-2012 01:12 AM

Re: DIY: Hemi 5.7L Spark Plug Change
Great write up and pics

One question....why not use an Iridium plug instead?

They last a lot longer.

Biggie65792000 11-28-2012 05:16 AM

Re: DIY: Hemi 5.7L Spark Plug Change

Originally Posted by Xjrguy (Post 716425)
Great write up and pics

One question....why not use an Iridium plug instead?

They last a lot longer.

There's been threads/ debates. IIRC, one side feels it's worth the added change interval and has not seen any problems using them (iridium) and the other side wants to stay true to manufacturer's recommendations and has heard and/ or experienced problems with anything besides the copper plugs. Search the forum and you'll find more details.

SixZeroFour 11-28-2012 10:06 AM

Re: DIY: Hemi 5.7L Spark Plug Change
Yup - There are a few reasons to stick with OEM plugs:

1) Although iridium/platinum plugs are meant to last longer between changes it doesn't really matter because you still need to stick with the Jeep recommended service interval (30k mi) while within your factory warranty period. Because of this you are throwing money out the window as the OEM plugs are far less expensive and will easily last 30k.

2) With this beautiful, hand crafted DIY it's an easy swap! :D:D:D
A complete swap of 16 plugs would now take me less than an hour and it only took 1.5 hours the first time around. Personally I'd rather have nice set of fresh plugs installed every 30k mi for the sake of $100 and 1 hour of my time.

3) Copper overall is also a better conductor and disperses heat better than platinum or iridium plugs do.

kkreit01 11-28-2012 10:23 AM

Re: DIY: Hemi 5.7L Spark Plug Change
Great write-up, and dead-on using OE plugs. Chryslers are weird like that.

Xjrguy 11-28-2012 05:58 PM

Re: DIY: Hemi 5.7L Spark Plug Change
ok thanks for the info on the iridium plugs. :thumbsup:

I put them in the V10 in my Viper and all the other cars and bikes I've owned and had great success.

Figured I would change to them with the 5.7 in the JGC and my 3.6 in the Wrangler.

Guess I will read up more on this then. :D

nek121328 11-28-2012 07:15 PM

Re: DIY: Hemi 5.7L Spark Plug Change
Not all Iridium plugs are made the same. The Champion version has copper cored center and ground electrodes and were installed in my WK2 by the dealer. No problem with warranty.

nathantw 11-28-2012 07:20 PM

Re: DIY: Hemi 5.7L Spark Plug Change
Thank you for the description and especially the pictures! I really, really appreciate it!

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