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Discussion Starter #1
Part 1 - Intro

This write-up will attempt to lay out the work needed to change the spark plugs on the 3.6L Pentastar engine, more specifically the version of the Pentastar which is found in the 2011+ Dodge Challenger. (Some sections may be of use to someone changing the spark plugs in other versions of the Pentastar, but Section 4 will likely be specific to the Challenger version only).

All of this is derived from my own experience and not taken from an official service manual or Haynes/Chilton manual. So this may not necessarily be the best/easiest way to go about this, but it is probably as much detail as you will find in one spot until the Haynes/Chilton’s manuals for the 2011+ Challengers get released.
For readability’s sake, I am going to split my write-up into several sections:


  • Intro (the part you’re reading now)
  • Spark Plug Choices/Specs
  • Tools to Consider
  • Removing the Intake Plenum
  • Replacing the Spark Plugs
  • Wrap-up
Also, I will attach relevant pictures to each section, inserting them inline for reference where possible.
¾

As far as general difficulty of the whole task is concerned, I would say it is a relatively straightforward task to change the spark plugs, but not necessarily an easy one.

Removing the intake plenum proved especially difficult and frustrating for me, and it probably will for you as well. There may a special type of wrench or socket that would have made this part easier to accomplish, but I didn’t have it if there is, and thus it took me several hours just to complete this portion of the job alone (x2 for reassembly).

Either way, you should probably keep the alcohol consumption to a minimum (trust me on this one!) and budget a full day’s worth of time to getting it all done. I have actually done this part of the process twice myself, and the first time it took me two days to complete (too many beers!), but I got it done in an afternoon the second time (4-5 hours). So take from that whatever you want.


Good luck, and may the Swartz be with you!
 

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Discussion Starter #2
Part 2: Spark Plug Choices/Specs

First, you are going to want to make sure you can procure yourself a set (6) of replacement spark plugs before you start tearing things apart. You can get them from your local Dodge dealership’s Parts Department (Champion), or you can get them from one of your local auto parts stores (Autolite/NGK). You will probably find that availability dictates your source/brand here.



Here’s the part numbers (and pertinent info for each brand) of spark plug currently available:

3.6L Pentastar spark plugs


  • Champion RER8ZWYCB4 (OEM)
    • Part # 9407 (MOPAR part # SP149125AD)
    • .043” gap (per Service Manual)
    • Torque to 13 lb/ft
  • Autolite XP Iridium
    • Part # XP5701
    • .044” gap (per Autolite)
    • Torque to 13 lb/ft
  • NGK Laser Iridium
    • Part # 1989
    • .043”/.044” gap (per Nuke)
    • Torque to 13 lb/ft
You may notice the difference in listed gaps of the various spark plugs above. That is due to a) what I’ve read, b) what I’ve seen, and c) what I think.


a) The Service Manual says the OE plugs should be gapped at .043”, and I am assuming that is a spec from Champion for their plug, so I have repeated it here.


b) The Autolite XP plugs listed .044” as their gap spec, and that’s what they were out of the box (most of them anyway), but I double-checked each spark plug before installing it.


c) I have no info on the NGKs either way, but I’m guessing you’ll be fine if you gap them at either .043” or .044” before installation. Just make sure they are all the same, whichever gap you settle upon.
 
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Discussion Starter #3 (Edited)
Part 3: Tools to Consider

Wrenches
Round up every different kind of wrench you can find in the 13mm size, as you will likely try all of them at some point in an effort to get the plenum brackets loose.

pic 1.jpg


Torque Wrench(s)
At the very least, you should have a 3/8” drive torque wrench, but a 1/4" drive torque wrench would be even better. If you only have the 3/8” drive one, you will need a 3/8” to 1/4" drive adapter to use with it most likely.

I know, I know, you are not supposed to use such things with torque wrenches, but we are torquing the small down to < 10 lb/ft, so you can use an adapter and get away with it (as long as you remember to account for the adapter by adding a lb/ft or two of torque).

Sockets, etc.
You will need the standard assortment of 3/8” drive and 1/4" drive ratchets, extensions, and sockets. The sockets will be metric and should include 8mm, 10mm, and 13mm, as well as a standard size 5/8” spark plug socket.

Specialty Tools
You should get a wire-style or feeler-gauge type spark plug gap tool if you do not have one. The gradual/sloping type should NOT be used!

Also, when I purchased my wire-style gapper, there were two versions available – the standard ignition version and the hi-energy ignition version. I went with the hi-energy ignition version because it had the gap wire that I needed (.044”), whereas the standard ignition version did not (closest gap available on it was .045” I believe).

EDIT: Since I first posted this particular post, there were some additional specialty tools I wanted to make note of. Since this post's already maxed out with the number of pics I can attach, I just created new posts at the end of the thread so I could attach new pics of these additional tools. You can go straight to the additional posts using these links:

Section 3; pt. 2
http://www.challengertalk.com/forums/3078913-post15.html

Section 3; pt. 3
http://www.challengertalk.com/forums/3079025-post16.html



¾



In order to torque down the plenum bolts, I resorted to making a specialty tool out of a 3/8” to 1/4" drive adapter, a 1/4" drive extension, a 1/4" drive ¼” socket, and a T30 bit (held by the ¼” socket). This was mostly needed because I was using the 3/8” drive torque wrench, and I wouldn’t have needed it if I had been using a 1/4" drive torque wrench. So adjust your tool selection accordingly.

pic 2.jpg
¾

Since the cylinder heads are aluminum, I had a T-handle spark plug tool I used to remove and insert the plugs to ensure I could be gentle and not break off the plugs inside the valve cover tube. It has a built-in wobbly extension that I wrapped with electrical tape to keep it from wobbling on me. Something like this certainly isn’t required, as it was mainly for my peace of mind. But if you’ve already got something like it in the tool-box, you might break it out and use it similarly.

pic 3.jpg

¾

I also found these little hooteramuses came in handy with the hardest to get plenum bracket bolt (only one of the hooteramuses actually) :

pic 4.jpg

I forget what those little things are called but I bought the set of them (3) at Harbor Freight for something like 8 cents...well, maybe a little more than that, but not much.

I used the 3/8” drive one in conjunction with the 13mm socket from this set of sockets:

pic 5.jpg

Those are called Grip-Tite sockets I believe, and they make all kinds of claims on the packaging and charge way too much money for them, and I have only ever found them to be useful while changing oil (holding onto the drain plug beats dropping it into the pan with the used oil)...until this project, which provided me another opportunity to use the sockets' ability to stay on a nut/bolt at any angle without falling off.


¾

And a can of compressed air!
No, your lungs won't work.
 
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Discussion Starter #4 (Edited)
Part 4: Removing the Intake Plenum

This is the hard part.

You will need to remove the air intake tube and throttle body (along with the assorted vacuum tubes and wiring harness connectors on each of these pieces) before you start.
This includes the PCV and Makeup lines coming off the back of the plenum. Once you have all that out of the way, it’s time to get down to the nitty-gritty…


The plenum is held down to the intake manifold by seven 8 mm bolts (T30).


pic 1.JPG



The plenum is also held in place by three brackets, one at the rear of the motor and two along the left side (driver’s side; next to coolant overflow reservoir).

The best way I found to get the plenum loose with the least amount of trouble (relatively speaking), was to unbolt the rear bracket and all the top bolts, then go at the two side brackets and get them loose enough to wiggle the plenum out from them and off the engine.

That process is what I will detail here.


1. Remove the two 13mm bolts holding the plenum to the rear bracket.

pic 2.JPG


2. Once you have those loose, you can go ahead and remove the two 13mm nuts holding the plenum to those two side brackets.

pic 3.JPG


3. Then you can remove the seven 8mm bolts holding the intake plenum down to the intake manifold .

pic 1.JPG


4. Now you just need to loosen the two side brackets’ bolts holding them to the cylinder head enough to get the plenum off.

pic 4.JPG


5. One of the bracket bolts is also the mount point for an A/C line. Loosening the bolt holding it in place up on the wheel well behind the strut cover will probably prove useful.

pic 6.JPG



That will give you some slack to move that A/C line around a little to be able to get to that bolt and nut on the plenum bracket. This particular bracket’s bolt and nut will be your nemesis for the next little bit.


The nut holds the A/C line in place on top of the bracket bolt’s 13mm head, so you’ve got to get the nut loose (removed completely), and then you have to go at the bolt again to get it loose, similar to the other bracket’s bolt on the same side.


Words alone cannot describe the frustration and discomfort that awaits you here…at least it was for me. Maybe it’s because my hands and wrist are too big to fit down in there; maybe it’s because all my tools seemed to be just a smidge too long, too short, not have the right angle of bend, etc. Whatever it was, this one bracket’s removal was the bane of my existence both times I had to remove the plenum on my car.


So basically what I’m trying to say is you’d better pack a sacked lunch for this part, because you could be there a while!


¾


Installation will be the reverse of removal, with the torque spec for the plenum to manifold bolts being approximately 6 lb/ft. I say “approximately” because the plenum itself has “7-9 Nm” molded into the top of its case, and if you translate that to lb/ft, you get 6 lb/ft. I was using my funky special adapter extension I detailed earlier, so I actually set my torque wrench to 7 lb/ft. Your situation may vary.


Once you have the plenum back on and torqued down, reattach the throttle body, air intake tube, and various vacuum hoses and wiring harness connections to each as they were removed. This includes the PCV and Makeup lines coming off the back of the plenum (PCV is on passenger’s side; Makeup line is on driver’s side).


¾


Now go wash your mouth out with soap, because I know you just used every cuss word you’ve ever heard and then invented a few of your very own as well!
 
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Discussion Starter #5 (Edited)
Part 5: Replacing the Spark Plugs

Even though the new spark plugs should all be pre-gapped to the correct gap, you should double-check them and make sure they are all gapped correctly before inserting them into the cylinder head and torqueing them down.
This part is fairly simple, but you will need to be careful:

  1. Wait until the cylinder head has cooled off completely!
  2. Disconnect each of the coil packs from the wiring harness.
  3. Remove the 10mm bolts holding the coil packs to the valve cover.
  4. Remove the coil packs by turning them a half turn or so and pulling up at the same time.
    There is a spark plug boot attached to the bottom of each coil pack that seats onto the spark plug at the bottom of the valve cover tube. Once the boot is loose from the spark plug, just pull it up and out.

  5. Blow out the spark plug tube inside the valve cover with the compressed air to remove any debris that might have found its way into the tube, e.g. die-electric grease dandruff from the plug boot, sand, etc.
    You’ll want to be thorough here, as anything left down in there will make its way into the combustion chamber once the spark plug has been removed, and that is NOT conducive to optimum air/fuel combustion!

  6. Remove spark plug and replace with new one.
    I recommend only hand tightening the plugs at insertion to make sure none get cross-threaded in cylinder head.

  7. Torque new one down (13 lb/ft!).
  8. Put some die-electric grease in the end of the plug boot.
  9. Replace coil pack/plug boot by slowly pushing down as you rotate the assembly to ensure snugness of boot on plug end.
  10. Hand tighten the 10mm bolt holding down the coil pack to the valve cover to make sure none get cross threaded.
  11. Torque down the 10mm bolts holding coil packs to valve cover.
    ?Torque spec? I don’t have it, and never knew it. I just used ratchet and socket to go an eighth turn past hand tight. Not too much, not too little. Use common sense here, and you’ll be fine.
 

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Discussion Starter #6 (Edited)
Part 6: Wrap-UP

This section contains some notes and such I had from when I replaced my spark plugs, and I wanted to include it somewhere in this write up for you to keep in mind while doing yours.
¾
The Champion brand plugs are what comes in the engine from the factory, and they are what you will get from the Dodge dealership’s Parts Department if you buy your replacements there.
I went with the Autolite XP Iridium kind when I replaced mine (I already had one of that kind in engine when general plug replacement was decided upon, so I just bought 5 more of same kind to save time, trouble, and money), and have no complaints at all.
I have put about 15K miles on them since changing them without any problems, and my MPG numbers, 0-60 times, etc. are all similar to when running the Champions. So I would say the Autolite XP plugs are a suitable choice for a replacement spark plug if you wish to use them.
I haven’t heard or read anything about the NGK’s being used in this engine. If you want to be a pioneer and try some in your car, please post up a review of their performance after a few thousand miles.
¾
WARNING: 12mm SPARK PLUGS MUST NOT BE OVER-TORQUED!
“The 3.6L Pentastar engine is the first Chrysler engine to use 12mm spark plugs. With the introduction of this smaller spark plug is a concern that can occur usually not seen with larger 14mm plugs - when the smaller 12mm spark plugs are over-torqued, the metal shell stretches, resulting in improper heat transfer from the ceramic through the shell. This in turn can cause engine damage, due to pre-ignition.”
Regardless of brand, torque spec is 13 lb/ft (17.5 Nm)
¾
There is a rubber gasket between the intake plenum and the intake manifold, but it is integrated into the bottom of the plenum and not removable. Further, no gasket sealant or silicone “goop” is necessary at assembly – just put the two pieces flush together and tighten/torque the bolts down.
¾
Depending on whether or not you are running a Catch Can (and how long you have been running it if you are), you may find that your intake plenum is coated in motor oil and even dripping with it once you get it off the engine. If this is the case, you may want to try to clean it some before you reinstall it after installing new plugs.
Mine was a little oily, so I did clean mine. I used WD-40 (or was it Carb-Choke cleaner?) on mine and allowed to dry for 12 hours or so while I finished up the rest of the tasks at hand. I’m sure someone will chastise me for my choice of cleaning chemicals, and rightly so, but my state of mind at the time wasn’t very good, so my car’s lucky I didn’t have anything more harmful at hand when I did the cleaning, because I probably would have used it!
¾
That’s about it. I will include some more pictures I took during the process on mine just to give you a visual reference of what things will look like through the whole process. Check those out below (attached).

EDIT:
A user asked me about the second to last picture in this post, and I realized it is a little out of place down here in section 6 when it should be up in the tool section. I would have posted it up there, but there is a limit to the number of pictures that can be attached to a single post, so I could not include this pic with the other tools.

If you were to take the tools shown in the last two pics of the tool section above, the pic in question down here is what the combination of those two tools looks like.

I forget what those little nut-driver things are called, but they have a socket driver on one end and a standard sized bolt head on the other. This allows you to use a socket without a ratchet by turning the socket via a wrench.

That's not something that will be needed very often, but in this case, on the left side bracket bolts, that little contraption was semi-useful because the sockets design kept it from falling off the bolt head even though the bolt is on a downward angle, and the nut-driver was a necessity because there was no room to get a ratchet to turn the socket once on the bolt head.

Clear as mud?
 

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After-Post Post

Well, that's about as good as I could get it to come out unfortunately.


I had it all typed up in a Word document with inline pics and everything, but things got all screwed up in the copy and paste between there and the New Post pages.


I probably should have seen that coming. Oh well, y'all are intelligent folks I reckon. You'll be able to figure it out.


The info's all there, it's just not as pretty as I wanted to it to be.


So set you to your tasks!!


Nuke, OUT!!
 
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I for one, really appreciate your write up here. I had NO idea it was this involved.

I miss the old days when changing plugs was a 10 minute job.
 
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Discussion Starter #9
I for one, really appreciate your write up here. I had NO idea it was this involved.

I miss the old days when changing plugs was a 10 minute job.
Thanks...I tried to include everything I gathered in researching the process beforehand for my plug replacement, as well as all the little 'gotchas' that didn't come up in research beforehand but which I learned the hard way after actually doing the process.
I figure it's better to include it all and let the reader filter out what they already knew or thought to be common sense.

But in doing so, I realize it's very possible I made the whole task sound more difficult, or 'undoable', than it really is.

Anyone that is mechanically inclined and has a good set of tools can probably do this. It's just that getting that damned plenum loose (and back on) is a real bas-turd...but it can be done...just not quickly.

I hear ya though on the longing for simpler times...I had a car once that required I clean the plugs about once a month cause they would foul so quickly. If that were the case with this engine, I think I would rather drink a cup of burnt transmission fluid each day until I died. I'm too tall and too old to be doing this plug swap process more than once a 100K miles!
 

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Discussion Starter #11
Thank you thank you thank you!!!! Nuke your the best!

Also like the color of your car...mine is same.
Glad I could help.

After you get your plugs changed, if you find I did something the hard way, or if you find some special wrench/socket/etc. made some part of the job easier, then please post an addendum post to this thread with the details.

I am not so vain as to think my process is the best approach, but it was the best approach for me at the time.

But if I missed something, overlooked something, or just generally did something the hard way, I'll be glad to edit my original posts to include new/better info or point to a post with an alternate idea on one of the steps.

Thanks,
Nuke
 

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WOOHOO!!

I finally figured out why I couldn't ever get the attached pics to insert inline with their respective text - their dimensions were too large.

So, I resized them to acceptable dimensions and inserted them inline with the text that talks about them.

WOOHOO!!

Man, that's been bothering me ever since I created this thread...now I can finally go out and resume my life, what's left of it...
 

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Discussion Starter #14
One more update:
it was brought to my attention that one of the pics in the last section is a little out of context (the one with the socket with a bolt head sticking out of it.), so I edited that section to add an explanation about that tool's origin, and I also edited the 3rd section with the tools to reflect the same (because that tool is the result of combining two of the tools from section 3).

Thanks to SoChallenged for pointing my inadequacies, I encourage others to do the same.
 

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Discussion Starter #15
Section 3; part two

I recent unpleasant experience with a spark plug gapper got me to thinking about my recommendation about buying a specific kind for this project. So I wanted to update this thread with some further info and suggestions regarding the gapper you might buy/use.

Back in Section 3 where I listed out the various tools I used, I talked about a special kind of spark plug gapper under the Specialty Tools section. Everything I said still stands, but as I just found out, all gappers are NOT created equal.

I recently changed the plugs on a vehicle which required me to buy another gapper to verify the plugs' gap settings before installation. The wire-style gapper I had bought previously did not have a wire for the gap I needed for these new plugs, so I purchased the standard ignition version this time (as opposed to the high-energy version I got for the Challenger). I did not get it from the same store though, and so the brand/quality of this newest one was not the same as my previous one.

Here's a pic of the two gappers side by side (previous one is on the left; new one is on the right):

gappers.jpg

As soon as I found a plug that needed its gap adjusted, I ran into a big problem: this new one was too flimsy to allow me to regap the plug using the gapper's built in electrode bending arm. Instead of changing the gap of the spark plug, the spark plug was changing the shape of the gapper.

It appears as though the metal the new gapper was made with was not up to snuff when it comes to gapping a plug. It could measure the existing gap, but it could not modify that gap. It just bent itself instead in weird contortions instead. Here's a pic of the new one with the bent side facing the camera:

bent gapper.jpg

Here's a pic of the old one; notice the color/type of metal used for each when constructing the regaping arm:

good gapper.jpg

So be careful if you buy yourself a gapper and get one of these wire style kind. If the electrode bending arm looks shiny and chrome, it's probably not going to work.

On the other hand, if you can get one with the smoke colored metal gap arm, you should be okay. Just a cursory touch can tell you what I am talking about and which one can be trusted.
 

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Discussion Starter #16 (Edited)
Section 3; part three

I also recently ran across a little tool which I purchased specifically for the Pentastar spark plug change, and I wanted to document it for anyone not aware of its existence.

There are two hose clamps you will need to disengage in the Challenger engine compartment which are difficult to get loose if you do not have the proper tool (both are on the PCV line onright side of engine/intake). Here is one such tool:

hose clamp 2.jpg

hose clamp.jpg

Notice the claws that can be moved back and forth, that's how it grabs the hose clamps it is so that the target hose clamp can be grabbed and held while pressure is applied/added to compress the clamp and get it move down the tube it's clamping

The jaws are driven by a worm screw that runs along the top of the tool, and that action is driven by with a 1/4 ratchet (no socket; just the ratchet.

There are only two of these clamps on the Pentastar that you need to worry about while doing the plug change, but I could not get anything else to work except this, so keep that in mind.
 

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Thank you for this great post. Your information saved me a lot of time. I was able to complete the job in 2 hours 30 minutes due to your instructions.
Two and half hours? TWO AND A HALF HOURS?!?

It took me twice that the 2nd time I did it, and I knew what to expect...

That's it, I'm taking out some of the detail from this thread, if I had to suffer, so should you!!

Just kidding of course, glad I could be of some help.

Nuke
 

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This really needs to be a sticky! Thanks for taking the trouble to document this.

What year 3.6 did you work on? My 2014 appears to have all the AC lines tucked back on the firewall. It's tough to get a camera back there, but I didn't see any AC lines attached to the plenum. Maybe I'm missing it. Anyway it'll be a while before I have to deal with it, so thanks again!
 

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This really needs to be a sticky! Thanks for taking the trouble to document this.

What year 3.6 did you work on? My 2014 appears to have all the AC lines tucked back on the firewall. It's tough to get a camera back there, but I didn't see any AC lines attached to the plenum. Maybe I'm missing it. Anyway it'll be a while before I have to deal with it, so thanks again!
Mine was a 2011, which was the 1st year of the Pentastar, so they may have rerouted the a/c lines in subsequent year's designs, maybe someone can check and update this thread if so.

I say they were a/c lines, but that's only because they were stainless steel and appeared to be going into/out of the compressor. They could have been for something else and just run through metal lines because they were so close to the exhaust manifolds.

Whatever they were, they ran alongside the left of the motor in between the exhaust manifolds and the fender well, and they used the rear-most plenum bracket's bolt to attach to for their own little bracket.

Them being in the way of getting to that bracket's bolt would be a great reason for rerouting their path up to front of the motor IMO, so I can certainly see where later models of the Pentastar would not have them hindering the access to the plenum bracket's bottom bolts at the exhaust manifold.

If that is the case, you non-2011 Pentastar gentlemen should consider yourselves lucky, cause those metal lines were a considerable hindrance to my efforts at loosening the bracket bolts. I called them names I'm ashamed to even admit I've ever even uttered out loud. But they deserved it at the time, AND THEY KNOW IT!
 
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