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Spark Plugs

8K views 34 replies 16 participants last post by  2005JGC 
#1 ·
I have about 46k on my 06 4.7 and i have yet to change my spark plugs... i think i am starting to notice my mpg's drop and a slight loss of power but it could just be me. I work about 12 hrs a day right now since its tax season and mechanics aren't open when i have time to take in my Jeep. Can i get some advice on changing the plugs myself and how much longer i can let them run with the current plugs in there... i got the Jeep with 23k on it so i doubt they've ever been changed, thanks in advance.

-Dave
 
#2 ·
According to the maintainence schedule it suggests spark plug replacement at 30k miles. When you replace them go with the oem plug, the part numbere is on the emissions lable under the hood. make sure to have a decent assortment of extensions, and some patience.
 
#3 ·
Yeah, and if it's anything like my 4.7 or my wife's 3.7, make sure you have some wobble extensions and universals. If I remember correctly, the back passenger's is a bitch. If you're on a schedule, start at the back of the motor and work your way forward. If you can get the back ones done, it's cake from there on out.
 
#15 ·
is everyone putting the copper spark plugs back in? I need to change mine but dont feel like doing it every 30,000 which you really need to do when it comes to copper plugs
 
#17 ·
It is HIGHLY suggested that you use the factory plug. there are known issues with using aftermarket plugs... I wont make a blanket statement that ALL aftermarket plugs will cause issues, but I dont know what ones. It is suggested that you use factory recommended plugs.
 
#19 ·
It is VERY VERY VERY important... I would change your plug wires once every 15k miles at LEAST.











ok, Im sorry, Im a douche, your 4.7l doesnt use sparkplug wires. It uses coil on plug technology.
 
#23 ·
#24 ·
Changing spark plugs per factory recommendation is very very important particularly if these are original equipment plugs. They do not use platinum tips so there is not much leeway in terms of plug life and gap erosion. Typically, factory installed platinum tipped plugs usually have a 100k mile replacement recommendation.

Instead of replacing them with OEM plugs, I usually specify double platinum plugs (platinum pads on the tip and electrode), just so I have some leeway on mileage, if I do not get to replacing them right away. These just cost slightly more but well worth it. It gives you more consistent performance over time since the plug gap remains constant and does not change over time.

One more thing, make sure you put a dab of anti-seize compound on the threads so next time you have to do it, the plugs will come out cleanly and easily.
 
#25 ·
Changing spark plugs per factory recommendation is very very important particularly if these are original equipment plugs. They do not use platinum tips so there is not much leeway in terms of plug life and gap erosion. Typically, factory installed platinum tipped plugs usually have a 100k mile replacement recommendation.

Instead of replacing them with OEM plugs, I usually specify double platinum plugs (platinum pads on the tip and electrode), just so I have some leeway on mileage, if I do not get to replacing them right away. These just cost slightly more but well worth it. It gives you more consistent performance over time since the plug gap remains constant and does not change over time.

One more thing, make sure you put a dab of anti-seize compound on the threads so next time you have to do it, the plugs will come out cleanly and easily.
As I have suggested, Using factory plugs is always suggested, but if not thats your thing.

What I really commented on is the fact that EVERY sparkplug manufacturer states that you should not put anything on the threads of sparkplugs, furthermore I have replaced alot of them and NEVER have problems, if the car has 30k miles or 280k miles.
 
#26 ·
Im pretty sure that the factory recommends everything to be done at the factory... thats why they charge ~450 bucks for spark plugs and a local mechanic will only charge ~150. Shit... if i was the factory i'd say the same thing... all the Stealership wants is to make $$ so it covers their a$$e$ on the back end for all the warranty work they do.

i didnt get my spark plugs from Jeep... and they work GREAT... so far no problems and i paid 1/4 the price.
 
#27 ·
I had a 2006 Laredo with the 3.7 and put over 60k miles on it and didn't change the plugs once. Car ran great and I averaged about 16-17MPG with over-sized tires. I never even looked to see what the service interval was. Shame on me...but I got away with it.

Now that i think about it, i'd like to see what those spark plugs looked like.
 
#28 ·
Interesting that plug wear seems to differ from engine to engine/vehicle to vehicle. My daughter's plugs on her 07 3.7L Liberty was well worn when I replaced them at 30K (opened up to .050-.060 gap), while my wife's 08 3.7L WK was pristine at 30k miles. Going over 30K miles with non-platinum tips is always risky as you cannot always tell how things are going on inside the combustion chamber.
 
#31 ·
I just changed the plugs in my wife's 2006 3.7 WK. She was at 70k with the originals, and started noticing a RPM drop at idle when the truck was warmed up. when i took out the original plugs the gap was around .65 for most of them :-( The back , passenger side one was not that hard to take out. I didnt use wobble extension, jsut a regular 6 inch extension. I used dielctric greas on the o-rings of the packs, as well as on the ceramic portions of the plug to create a nice seal on the rubber boot. I also used a torque wrench to tighten all the plugs down to 20ftlbs...this is somewhere you dont wanna guess at.:thumbsup: oh..and i just used NGK plugs.
 
#35 ·
I just changed the plugs in my wife's 2006 3.7 WK. She was at 70k with the originals, and started noticing a RPM drop at idle when the truck was warmed up. when i took out the original plugs the gap was around .65 for most of them :-( The back , passenger side one was not that hard to take out. I didnt use wobble extension, jsut a regular 6 inch extension. I used dielctric greas on the o-rings of the packs, as well as on the ceramic portions of the plug to create a nice seal on the rubber boot. I also used a torque wrench to tighten all the plugs down to 20ftlbs...this is somewhere you dont wanna guess at.:thumbsup: oh..and i just used NGK plugs.

Right on the mopar spark plug box it gives a torque angle. If there is a crush washer I think it says 1/4 turn or 1/2 turn after seating the plug, and without the crush washer it says 1/16th of a turn... I have never had any problems using this method of torquing.
 
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