HOW TO: Change Spark-Plugs

[KJ2005]

Autolite XP Xrtreme Performance

Awsome write up. I should've read it before I swapped my plugs but got by ok with a long extention and removing the air filter pipe and coolant box.

As noted here:

http://www.lostkjs.com/forum/phpBB2/viewtopic.php?t=31499

I replaced my plugs with Autolite XP Xrtreme Performance iridium enhanced plugs. I recommend these for those swapping out the plug in the KJ.

 

[JeepJeepster]

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.

How can you tell? I told the guy at the counter that I wanted double platinums.. Guess you should never assume.

What do I have, just single platinums?

 

[67Customs]

After checking out the Autolite site, they don't show a part number for the double platinums and the one for the single platinums is different than what you have pictured.

Do they have double platinums for the 3.7L? If not, what is the correct number for the single platinums for the 3.7L?

 

[tjkj2002]

JeepJeepsterQuote:
Originally Posted by tjkj2002
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.

How can you tell? I told the guy at the counter that I wanted double platinums.. Guess you should never assume.

What do I have, just single platinums?

Sorry for the very late response.

You must be registered for see images

Largest pic I could find.



It will say on the box if it is just a single platnuim(just stated as "platnuim plugs") or double platnuim.

 

[Dave]

^^^Ok guys, I was totally confused on this myself.

When I looked up the Autolite Platinum/double Platinum I got the following.

02-04 - Autolite Platinum = AP3923
Double Platinum = NOT LISTED

05-07 - Autolite Platinum = AP5224
Double Platinum = APP5224

Then it showed the gap on all of the above to be .035?

My 05 FSM shows NGK - ZFR6F-11G with .042 gap and the sticker under the hood of mine showed the gap as .040 for the NGK plug. This is for my 05 KJ. So I just got frustrated and went to NAPA and got the NGK's and made sure they were at .040 and put them in.

Why the numbers were different for the different years and not even listing a double platinum for 02-04 I have no clue. Why the gap was listed different I have no clue. Did they change the heat range and gap between model years for some reason or was the book wrong??? It is the same motor.

Anyway, I got the NGK's in and gapped at .040 per the sticker under the hood on my 05 MY and mine is running smooth.

Dave

 

[tjkj2002]

^^^Ok guys, I was totally confused on this myself.

When I looked up the Autolite Platinum/double Platinum I got the following.

02-04 - Autolite Platinum = AP3923
Double Platinum = NOT LISTED

05-07 - Autolite Platinum = AP5224
Double Platinum = APP5224

Then it showed the gap on all of the above to be .035?

My 05 FSM shows NGK - ZFR6F-11G with .042 gap and the sticker under the hood of mine showed the gap as .040 for the NGK plug. This is for my 05 KJ. So I just got frustrated and went to NAPA and got the NGK's and made sure they were at .040 and put them in.

Why the numbers were different for the different years and not even listing a double platinum for 02-04 I have no clue. Why the gap was listed different I have no clue. Did they change the heat range and gap between model years for some reason or was the book wrong??? It is the same motor.

Anyway, I got the NGK's in and gapped at .040 per the sticker under the hood on my 05 MY and mine is running smooth.

Dave

The same plugs for '05+ KJ's will work in '02-'04 KJ's.The platnuim plugs are pregapped,not always the correct gap but each part# covers many,many vehicles so they gap them at the most used gap.You must use a special gapper(plastic or compsite) to gap platnuim plugs our you will destroy them.

Always go by what the emission sticker under your hood says for plug gap.

 

[67Customs]

When I looked up the Autolite Platinum/double Platinum I got the following.

02-04 - Autolite Platinum = AP3923
Double Platinum = NOT LISTED

05-07 - Autolite Platinum = AP5224
Double Platinum = APP5224

That completely explains it. I didn't even think about there being different plugs for the different years. I assumed they would all be the same.

 

[tjkj2002]

That completely explains it. I didn't even think about there being different plugs for the different years. I assumed they would all be the same.

All 3.7's use the same plugs,'02-'09+.

 

[JeepJeepster]

Ahh crap, so I probably dont have DD's. haha.

Guess Ill get it at 60k.

 

[Dave]

All 3.7's use the same plugs,'02-'09+.

Yea, you would think they should. It is the same motor. But as I said in my post above, different plug numbers were listed for different years of the KJ for Autolite Platinum and Double Platinum. And they didn't even list a Double Platinum for 02-04 MY. And they were showing the gap as .035 when mine clearly states .040 so go figure.

You would think that the numbers would be the same, and the only difference being the prefix of AP for Platinum or APP for the Double Platinum. So I still don't know what is going on with that.

That's when I got frustrated with it and just went to NAPA and got the factory spec NGK's and gapped them to .040 like it says on the sticker under the hood on mine. FWIW, the stock NGK's I got at NAPA were under $20 for all 6 and a piece of cake to change, so I will change them again in 25,000 miles, cause that's all I think they are good for....in my opinion.

Dave

 

[tjkj2002]

Yea, you would think they should. It is the same motor. But as I said in my post above, different plug numbers were listed for different years of the KJ for Autolite Platinum and Double Platinum. And they didn't even list a Double Platinum for 02-04 MY. And they were showing the gap as .035 when mine clearly states .040 so go figure.

You would think that the numbers would be the same, and the only difference being the prefix of AP for Platinum or APP for the Double Platinum. So I still don't know what is going on with that.

That's when I got frustrated with it and just went to NAPA and got the factory spec NGK's and gapped them to .040 like it says on the sticker under the hood on mine. FWIW, the stock NGK's I got at NAPA were under $20 for all 6 and a piece of cake to change, so I will change them again in 25,000 miles, cause that's all I think they are good for....in my opinion.

Dave

Different part#'s due to different "pre-gap".Look at any other plug and you will find that the 3.7,no matter what Chrysler vehicle or year,uses the same plug.

I deal with plug changes everyday,have done alot of KJ's among many other vehicles,and all 3.7's use the same plugs no matter the year.


Look at the older SBC's,they all use the same plugs,though there are(last time I checked) over 50 part #'s for older SBC engines even though they are the same plug,and that is just from Autolite.

 

[Jeepin05]

Definitely great write-up.

I have an extended lifetime warranty from Chrysler on my 05, so I have been letting them do every little piece of maintenance at the dealer. I couldn't see paying them so much for doing the plugs, so I did this myself last night. It totaled just around $20 with the Autolite Platinum's, woohoo!

This thread helped a lot as I knew what I was getting myself into, it ended up being quite a bit easier than a GM 3.8 (my former 2 cars, love that motor). I will admit though, that the coil electrical connectors were the hardest thing to disconnect, especially the passenger side back one (#6?). I didn't really want to move the coolant tank as others suggested, but I think I will next time.

I have about 54k, and it did have the expected NGK's in there, which makes me wonder if they were the originals...

Anyways, it seems to have a little more pep now.

Thanks for the great write-up!

 

[MoreTorque06]

I just changed my plugs to Autolite double plats.

A lot easier than I expected. The only thing I removed was the intake tube. Othewise I got it done with just a 6" and 3" 3/8" socket extension. All cheapo walmart tools. Took about 45min.

At 86k, the stock plugs were really, really bad. I bought the truck with 77k on it during winter so I have been waiting for decent temps to change them. Ill probably do them once a year now.

Truck runs a ton better now.

 

[candpliberty]

Even after I read this thread, One of those rubber seals inside the coil pack disconnects fell down into the intake manifold! GASP! Solution? I have a tool I rigged for cleaning condenser coils under newer refrigerators made out of a vacuum cleaner crevase tool and some 18" long, 1/4" and 3/8" hose, RTVed to the end. (Two hoses for different applications) I used the smaller one so the seal wouldn't get sucked into the shop vac. Worked like charm. Next time I'll tuck a rag down around the coil pack keep it from falling in. I also applied some dielectric grease on the seals before packing them back in the disconnect. What a PITA!

(blarg)

 

[ridenby]

changed plugs yesterday,suprise,suprise,it had ngk in it wish i know how to post pictures,these were done,wore out.runs well,little smoother,maybe i will get more than 16mpg,think o2 sensers might be next.glad i found this site,#6 was pain anyway.

 

[LibertyTC]

Glad I found this thread !

Really good how to guide.
I was Leary about replacing the plugs myself until I found this thread. I accomplished the task in about 1.5 hours. I used NGK V-power ZFR6F-11g and found that they were dead on .040 all of them. The stock old plugs look good except the gap was now about .049 from wear at only 14k miles.
I purchased a new 5/8 plug socket to ensure that the new rubber insert would hold for the plug installation. For absolute ease I moved back the overflow tank and moved away the throttle body intake hose, then there was clearance to the plugs on the left side. While on the left side, I found a bonus block heater cord, even though it was not listed on the build sheet. I suppose it is true that all Jeeps shipped to Canada come with one!!
I also found this funny YouTube video which helped me figure out how to remove the coil pack wire clips. Too bad in this video there was no mention of the die-electric grease to insulator of plug/inside bottom of coil. I only used the compressed air once the coil packs were off. Also used air inside the bottom of coil pack to get the dust out of there too.
Video: http://www.youtube.com/watch?v=DxsEOCqhHx8

 

[LibertyTom]

ROFLMAO!!! very informative youtube video LOLsmashfreakB.gif

 

[draganjr]

What is the torque value of the spark plug and the bolt for the coil pack?

Thank you.

 

[Dave]

What is the torque value of the spark plug and the bolt for the coil pack?

Thank you.

Snug the plugs up by hand + 1/2 to 3/4 of a turn. That's the way I do it. Aluminum heads and threads so I do it that way and put a little anti-seize on the plug threads and a little dialectic grease on the 0-ring seal on the coil pak's. The coil pak bolt was 10mm.

Dave

 

[jas32]

Just did spark plug change 2 weeks ago before I saw this write-up and found this write-up is exactly the procedure that I did. Just a few comments to add.

1. After removing the coil-on-plug on each cylinder, and before removing the plug, I put my shop vac nozzle on top of the plug to suck any loose dirt that may be there. Compressed air is probably as effective but a good mechanic friend told me a long time ago that with compressed air you just move dirt around.
2. Like some people I did not see a need for removing the coolant reservoir. I just used a single flex joint and got to the #6 plug with no problems.

Just a reminder to everyone. It is important that plugs are changed per recommended schedule (every 30K), particularly when replacing the original plug (which are obviously the least expensive plugs money can buy). I observed on my KJ that at 30K the plug tip erosion was approx. +0.015'-0.020". I would think another 15-20K miles would have resulted in excessive plug tip erosion to result in potential engine misfire which could lead to some other (bigger) problems (e.g. catalyst overheat).

Platinum tipped plugs could last longer than 30K (they typically last 100K) but since they are fairly easy to change and quite inexpensive, it is still good insurance to replace them per recommended schedule, besides, replacing plugs is good insurance against freezing the plug in the cylinder head.