The manual for my wife's 2009 Jeep Liberty calls for replacement of spark plugs every 30,000 miles. I'm not one to buck the owner's manual, but 30k seems low for mileage on spark plugs. Thoughts?
Jeep Liberty Spark Plugs
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Jeez, are they straight copper plugs? I didn't know they still used those.
The change interval on the plugs on our former Town & Country was 100k miles, but they were dual-plat plugs.
The change interval on the plugs on our former Town & Country was 100k miles, but they were dual-plat plugs.
Change them per recommendation with the exact kind that came out.
I said the same thing about the 08 I have. I'd change them at 30K put anti-seize on the new ones. The heads are aluminum. Go with an NGK plug, Iradium or platinum and they'll probably last 100K. IIRC a mechanic told me they used a standard plug in the 3.7L engine, but I don't know for sure since I haven't changed mine. He did tell me to change them at 30K and use a better plug and anti-seize on the threads. I'll be changing mine at 30K.
Originally Posted By: Hokiefyd
Jeez, are they straight copper plugs? I didn't know they still used those.
Yes they are. The Platinum plugs often make Jeeps throw a misfire code.
Jeez, are they straight copper plugs? I didn't know they still used those.
Yes they are. The Platinum plugs often make Jeeps throw a misfire code.
Our Jeeps also say 30k. In the Wrangler they don't make it that far before the engine starts missing (2.4L I4) In the Grand, after 30k when you change the plugs the difference - in smoothness and mpg - are noticeable. (4.0 I6)
You've got the 3.7L V6, right? Your engine might not use plugs the way ours do so perhaps pulling one to have a look at condition is a good idea. Or you could change at 30k, note if there's any change, and go from there.
You've got the 3.7L V6, right? Your engine might not use plugs the way ours do so perhaps pulling one to have a look at condition is a good idea. Or you could change at 30k, note if there's any change, and go from there.
Yes, it is the 3.7 V6. I'm not a mechanically inclined, but I like to do as much work on my vehicles as possible (so far mostly oil changes) I just looked at the engine for the plugs and had trouble finding them. Does anyone change their own plugs or just have the garage do it?
Same with Hemi - 16 plugs every 30k. For some reason, most Chryslers think they run better with copper plugs. My 2.0 Neon was the same.
In my experience with Chryslers, they run good on Champion plugs.
Not sure what they recommend, but I always replace with OEM spec. (which has already been said here)
NGK coppers in my Saturns, NGK plats in my old Nissan, Champion coppers in my old Neon.
Not sure what they recommend, but I always replace with OEM spec. (which has already been said here)
NGK coppers in my Saturns, NGK plats in my old Nissan, Champion coppers in my old Neon.
The 3.7 in your Liberty is in the same engine family as the 4.7 in my Durango. The 4.7 calls for copper plugs, too.
It struck me as odd that a modern engine would still spec a copper plug, especially nowadays when low maintenance is pushed as a selling point, and platinum plugs can go 75-100k miles before replacement.
I wound up using basic coppers(Autolite) as my research turned up that they're best suited for this engine for smooth idle, no missing, etc. and I'm satisfied with them.
Is anyone aware of any other manufacturers still spec'ing copper plugs in their newer engines?
It struck me as odd that a modern engine would still spec a copper plug, especially nowadays when low maintenance is pushed as a selling point, and platinum plugs can go 75-100k miles before replacement.
I wound up using basic coppers(Autolite) as my research turned up that they're best suited for this engine for smooth idle, no missing, etc. and I'm satisfied with them.
Is anyone aware of any other manufacturers still spec'ing copper plugs in their newer engines?
My mechanic friend said he's seen people push those plugs way past 30K and end up stripping the heads taking them out. Its good business for him. I'll do some research into getting a CEL from platinum plugs before I change mine, glad I read this thread. But I'll be sure to coat the new threads with some anti-seize.
OP the best way to see where the plugs are on your 3.7L Liberty is look up from under it, or with a mechanics mirror. They are fairly easy to get at. I prefer to change my own plugs so I can get them out at some later point in time. I've removed plugs that must have been installed by Mighty Joe Young or King Kong, I would rather not have them cross threaded or stripped by someone in a hurry to beat the clock changing them.
I had someone once do plugs on my 93 Aerostar and he decided to change 5 of the 6 plugs, it happens quite often.
OP the best way to see where the plugs are on your 3.7L Liberty is look up from under it, or with a mechanics mirror. They are fairly easy to get at. I prefer to change my own plugs so I can get them out at some later point in time. I've removed plugs that must have been installed by Mighty Joe Young or King Kong, I would rather not have them cross threaded or stripped by someone in a hurry to beat the clock changing them.
I had someone once do plugs on my 93 Aerostar and he decided to change 5 of the 6 plugs, it happens quite often.
To answer the question about a DYI plug change, I've never worked on a 3.7. But, since they're closely related, I'd assume they're similar.
The ignition is coil-on-plug, so near the top of the engine look for the individual coils the sit atop the plugs. 3 on each side(duh, lol). Remove the single nut that holds down the coil and gently pull coil off. You then have access to the plug.
One side will have easy access blocked by intake accordian tube that you'll need to remove. Use anti-seize and easy on the torque as the heads are aluminum.
Not hard IMO. Have on hand a few socket extensions and swivel joints.
The ignition is coil-on-plug, so near the top of the engine look for the individual coils the sit atop the plugs. 3 on each side(duh, lol). Remove the single nut that holds down the coil and gently pull coil off. You then have access to the plug.
One side will have easy access blocked by intake accordian tube that you'll need to remove. Use anti-seize and easy on the torque as the heads are aluminum.
Not hard IMO. Have on hand a few socket extensions and swivel joints.
Some sophisticated engines there at Chrysler........
C-O-P ignition engines like Iridiums ND or NGK, dual fire like Cu core or Plat (these are cu core too, std plug should be called Inconel - the firing tip has NOTHING to do with the plug core!!!). Nothing likes BOSCH platinum - that would throw a code) Normal plats will not light the MIL unless you installed them wrong, or didnt gap them correctly or incorrect heat range or length from nut to terminal.
I would think the 3.7 is a dist or dual fire (double ended resonanant waste spark ala 90's mustang 302, Ranger 2.3) But I have not popped the hood on one of them.
I would think the 3.7 is a dist or dual fire (double ended resonanant waste spark ala 90's mustang 302, Ranger 2.3) But I have not popped the hood on one of them.
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Run NGK Platinums.Some Chryslers have them.Durango Hybrid is one of those,Go to the NGK company site and look up plugs for the 3.7. They will show standard and Platinums.I'm going to put the Platinums in my Hemi.
Just run the copper champs and call it a day.
It would take about an hour and a couple beers to change them out on a 3.7. Put some anti sieze on the new ones before you put them back in.
http://www.wkjeeps.com/wk_sparkplugs.htm
It would take about an hour and a couple beers to change them out on a 3.7. Put some anti sieze on the new ones before you put them back in.
http://www.wkjeeps.com/wk_sparkplugs.htm
I would prefer to use a Platinum or Iridium plug in my Liberty. I had no reason to believe they wouldn't work, although this thread did cast some doubt.
Arco-Good point about Bosch plugs, nothing likes them, that pretty much sums it up. I'd rather use something other than copper in my Liberty, and would prefer to stay clear of Champion plugs too. That pretty much leaves me with NGK when I'm ready to do the job.
Arco-Good point about Bosch plugs, nothing likes them, that pretty much sums it up. I'd rather use something other than copper in my Liberty, and would prefer to stay clear of Champion plugs too. That pretty much leaves me with NGK when I'm ready to do the job.
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From a performance perspective going 100K on plugs is outright ridicolous. I think its a sales hype personally. Most people don't keep their cars long enough to find out if they will last 100K.
What I DO know is that my car came from the factory with NGK Iridium plugs and are recommended to be changed by my Tuner every 15K-20K max. What people fail to realize is there is a performance penalty for going long extended times on spark plugs. In your 100hp Civic going to get groceries you may never see it, but if your in a mini van with 8 people in the car, or a 4x4 trying to pull a steep grade, or a High Performance sports car trying to get an extra 1/10 in the quarter mile, Spark Plugs make or break the performance of your engine. So CHANGE THEM every 30K if Jeep says to if not sooner and keep your JEEP at its Peak performance.
To me in the end the extra cost is well worth it in gas saved and consistant HP and TQ over the life of the Engine.
What I DO know is that my car came from the factory with NGK Iridium plugs and are recommended to be changed by my Tuner every 15K-20K max. What people fail to realize is there is a performance penalty for going long extended times on spark plugs. In your 100hp Civic going to get groceries you may never see it, but if your in a mini van with 8 people in the car, or a 4x4 trying to pull a steep grade, or a High Performance sports car trying to get an extra 1/10 in the quarter mile, Spark Plugs make or break the performance of your engine. So CHANGE THEM every 30K if Jeep says to if not sooner and keep your JEEP at its Peak performance.
To me in the end the extra cost is well worth it in gas saved and consistant HP and TQ over the life of the Engine.
Originally Posted By: Jeffs2006EvoIX
From a performance perspective going 100K on plugs is outright ridicolous. I think its a sales hype personally. Most people don't keep their cars long enough to find out if they will last 100K.
Your EVO and a Liberty are two totally different animals. I'm sure there is some slight degradation of plug performance if pushed to factory replacement recs, but unless like you say the engines being pushed hard I doubt it's really noticable.
The 2.5L in my SVT has double plats that according to the owners manual could go 100k, but I replaced them at 70k as the engine gets worked out occasionally and I want to maintain peak performance. When pulled the plugs looked good and I would imagine they'd easily have made 100k.
OTOH, the 4.7 plugs I pulled to replace at 130k had virtually no electrode remaining. Kicker to that is i'll never know how many miles were on those(bought used at 120k), but they were stock P/N Champions that very well could've been In since day one. Even in their poor condition, the truck idled smooth, no missing, no CEL. Just changed 'em for maintenance sake.
I guess my point is unless there's drivability issues(rough idle/CEL), factory rec'ed replacement schedule is more than adequate and changing plugs early just for the sake of doing so is equivelent to dumping synth oil at 3k- a waste of $$$.
But hey, it's not like it's my money. Do whatever floats it for ya! I don't get the iridium fad, either. 2x Plat gives all the longevity you need. It's a spark plug, not a bolt-on performance mod opportunity. It provides a spark or doesn't.
The 3L in the Mazda won't be getting new 2x plats 'till at least 70k.
From a performance perspective going 100K on plugs is outright ridicolous. I think its a sales hype personally. Most people don't keep their cars long enough to find out if they will last 100K.
Your EVO and a Liberty are two totally different animals. I'm sure there is some slight degradation of plug performance if pushed to factory replacement recs, but unless like you say the engines being pushed hard I doubt it's really noticable.
The 2.5L in my SVT has double plats that according to the owners manual could go 100k, but I replaced them at 70k as the engine gets worked out occasionally and I want to maintain peak performance. When pulled the plugs looked good and I would imagine they'd easily have made 100k.
OTOH, the 4.7 plugs I pulled to replace at 130k had virtually no electrode remaining. Kicker to that is i'll never know how many miles were on those(bought used at 120k), but they were stock P/N Champions that very well could've been In since day one. Even in their poor condition, the truck idled smooth, no missing, no CEL. Just changed 'em for maintenance sake.
I guess my point is unless there's drivability issues(rough idle/CEL), factory rec'ed replacement schedule is more than adequate and changing plugs early just for the sake of doing so is equivelent to dumping synth oil at 3k- a waste of $$$.
But hey, it's not like it's my money. Do whatever floats it for ya! I don't get the iridium fad, either. 2x Plat gives all the longevity you need. It's a spark plug, not a bolt-on performance mod opportunity. It provides a spark or doesn't.
The 3L in the Mazda won't be getting new 2x plats 'till at least 70k.
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