Jeep Liberty Spark Plugs

[caravanmike]

Originally Posted By: Chris Meutsch
Some sophisticated engines there at Chrysler........
sophistication doesn't always equal better! besides the tensioner bearings are holding up fine on these models.

on my 2006 liberty i am using the stock ngk's. i change them right at 30k, they can go for more miles. but with any aluminum head i like to get them out early so the threads are protected!

 

[Jeffs2006EvoIX]

Im just one to use preventive maintenance. I would rather change stuff BEFORE they NEED to be changed. That is all I am saying. Spark Plugs are relitively cheap. Waiting till your car idles wierd or your losing power to me is counter productive. Im in a different automotive mind. I seek maximum HP and TQ and will change my plugs often if it keeps that HP and TQ reliable. When I was running WMI I was changing plugs every 5K miles.

But you are right, this is a JEEP not an EVO, but I see all cars in the "performance" eye. Even a Jeep.

 

[Hokiefyd]

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.


I pulled the original 140k mile plugs out of my '97 Cadillac (32V DOHC Northstar) and they were still pretty good. They were dual-plat AC plugs. I put new OEM ones back in and kept driving. No real change to performance or mileage.

If you meant that going 100k miles on _COPPER_ plugs, I'd agree. But with modern spark plugs, performance really does degrade very little with age and mileage.

The new Jeep Wrangler should also run 100k on its plugs, as it has the same engine as the minivans (3.8L V-6).

 

[Jeffs2006EvoIX]

Every Car is different. My Iridium plugs could go 100K in some cars go a recommended 30K in my car. Thats if you go by OEM specs.

I am sure the Jeep falls into the 100K category, but I would never go that far on plugs. Seen too many issues of stripped threads in alum heads with plugs being in that long. You would think most Auto Companies would use an Anti seize on the threads, but you would be surprised how many do not.

Again, I side on the side of caution. Most people don't see hiccups on their car because they don't really notice, doesn't mean its not happening. Personally, I data log my car almost weekly, and its on the dyno, well used to almost monthly, to extract the most HP and TQ possible. You may not notice the difference, but your car does.

Go with the 30K JEEP Recommends, you will be fine, just keep using a NGK or Denso Plug and your Good. Plats, or Iridium are very good

 

[tinmanSC]

Originally Posted By: Chris142
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.

He's got it right. That's why exactly. It is very common on the Jeep forums for people to have this issue.

 

[Hokiefyd]

Originally Posted By: Jeffs2006EvoIX
You would think most Auto Companies would use an Anti seize on the threads, but you would be surprised how many do not.


Some spark plug manufacturers have a coating on the plugs that prevents corrosion. For example, AC uses a nickel coating on their plugs that is supposed to prevent them seizing in the heads. I was afraid of stripping the threads on the Cadillac I had, so I used an impact gun to remove them. A Cadillac powertrain engineer suggested that to me. I was scared to do it, but it actually worked like a charm. The plugs came out clean as a whistle.

I agree that regardless of the interval, going by the manufacturer recommendation won't get you into trouble.

 

[demarpaint]

I'd never leave a plug in an engine for 100,000 miles, not under my driving condtions. First off if I didn't install them myself I'd be afraid of them rotting in the head. The only way I'd be sure they had anti-seize on them is if I put them in myself. Plugs are cheap, installing a Heli-coil on a stripped head can be a major PITA, or very costly. I'd rather follow the OM, in my case Jeep says 30K plug change, that's what I'll do.

 

[Jeffs2006EvoIX]

Originally Posted By: tinmanSC
Originally Posted By: Chris142
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.

He's got it right. That's why exactly. It is very common on the Jeep forums for people to have this issue.


Are the JEEPS Ignition systems that weak that they missfire when not using Copper Plugs? Wow thats crazy. I would install a MSD ignition pack on that bad boy then. Or use some better plug wires or something Thats crazy. Throwing codes with Plat plugs.

 

[Hokiefyd]

I think the notion that it's a "Jeep" issue is highly generalized. It has to do with this engine design apparently. The 3.7L is not only found in Jeeps, but in Dodge trucks as well (with the same copper plug requirement). And the Hemi is not found in Jeeps, but still has the copper plug requirement. And if anyone who has a JK Wrangler can confirm that the 3.8L V-6 has dual-plat plugs with a 100k mile change interval (like it does in the minivans), that would pretty much confirm that it's an engine-specific issue, and not a "Jeep" issue.

 

[Hokiefyd]

Originally Posted By: demarpaint
I'd never leave a plug in an engine for 100,000 miles, not under my driving condtions.


I'd never leave a copper plug in an engine that long under ANY driving conditions. The 30k mile interval makes perfect sense, knowing that they're copper plugs.

 

[demarpaint]

Yes, at 30K a copper plug is pretty much done, sure there are exceptions. However I wouldn't leave a factory installed Platinum or Iridium plug with a 100,000 mile interval in that long either. Unless I installed it myself and knew it would come out of the head at some later date w/o stripping threads. I'm not saying the plug can't handle that service life, it is a matter of being able to remove it several years later. I'd want to take it out at 25-30,000 miles. Inspect or replace it, coat it with anti-seize so 7-10 years later when I have 100,000 miles on the car it will come out of an aluminum head.

 

[MI_Roger]

Originally Posted By: outoforder
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?


Easiest plugs I've ever changed on a V-configuration engine!

The plugs sit on the top of the engine rather than the side. Each plug is covered by its own "coil on plug" ignitor which is held by a single screw. Jeep even cast a notch in the windshield washer soluiton bottle(?) on the passenger firewall to make access to that plug just as easy as the other five.

 

[47HO]

My '02 Jeep (4.7 H.O.) came from the factory with platinum plugs, and they are Champions. The manual still recommends 30k mile changes. I've run them to 50k miles with no problems or appreciable wear. I always replace them with the same ne plugs.

 

[meep]

I own a 3.7 and have champion plats waiting to go in. the jeep forum I frequent suggests that the 3.7 is not as picky about copper as the V8s are.

I think some of the bad rap comes from bosch. I've used a lot of bosch plats on imports with no trouble. But my brother and several other folks I know have had problems with platinums... that all happened to be bosch. so is it the material, or the manufacturer.

I wanted NGK dbl plats for the 3.7, but they were pricey and the champion plats should be good enuf. Car goes to work and back... just needs to run.

M

 

[SteveSRT8]

The 5.7 and 6.1 are a great example of the [censored] copper plug rumor.

New gen Hemi's run great on almost any plug. Copper plugs are used for price point only, it's a bean counter thing.

I have asked before, please find me any car sold in the US that ships with a copper plug. Besides Chrysler.

 

[ARCOgraphite]

Originally Posted By: Jeffs2006EvoIX
Originally Posted By: tinmanSC
Originally Posted By: Chris142
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.

He's got it right. That's why exactly. It is very common on the Jeep forums for people to have this issue.


Are the JEEPS Ignition systems that weak that they missfire when not using Copper Plugs? Wow thats crazy. I would install a MSD ignition pack on that bad boy then. Or use some better plug wires or something Thats crazy. Throwing codes with Plat plugs.
That's BOLognA!. Platinum plugs do not make a car throw a code. Some guy who doesnt know how to replace plugs makes a car throw a code. BTW ALL PLUGS ARE COPPER. Like I had written recently, the firing tips may be: nickel steel, platinum or iridium. What you guys call copper plugs are steel plugs. Jeepers!! You guys better stick to oil!

 

[ARCOgraphite]

meep is correct, any problems with plat plugs would be the odd design bosch plats exclusively - its a design issue - the firing electrode is normally too cold and shrouded by the insulator for light throttle crusing - they can work well in racing - in high power and load applications. Bosch makes a good $2- steel Cu core plug if the heat range works in your car. Nippon Denso makes the best engineered and highest quality plug - but compatible heat range is the #1 issue to get correct on a plug on a lambda smog engine.

 

[Chris142]

Originally Posted By: ARCOgraphite
Platinum plugs do not make a car throw a code. Some guy who doesnt know how to replace plugs makes a car throw a code. BTW ALL PLUGS ARE COPPER. Like I had written recently, the firing tips may be: nickel steel, platinum or iridium. What you guys call copper plugs are steel plugs. Jeepers!! You guys better stick to oil!
Ok I'll make you a deal If you will show up here with a set of single Platinum plugs for my 4.0L Jeep you can install them. After the install if I get a P300, 301,302,303,304,305 or 306 code you must remove the plugs, reinstall the plugs that you took out of my jeep and your going to buy me a steak dinner. If there is no codes thrown I'll pay you for the plugs and I'll buy the steak.

 

[MNgopher]

Knowing they are copper plugs means 30,000 miles is the right interval. If it is as easy as was stated above, its really not a big deal at all.

I'm guessing ARCOgraphite hasn't spent much time with a the old 4.0l in the Jeep lineup. It is a known issue that platinum plugs and that engine generally don't get along and it isn't limited to Bosch plugs. Older models prior to the the COP setup always used champion copper plugs, and with the COP setup some went to NGK's from the factory, always copper.

As Chris stated the first question when someone changes the plugs and gets a misfire code is what kind of plug did you use? Platinum plugs are that list of not so great ideas. (For that engine anyways...)

 

[Rooy]

Originally Posted By: SteveSRT8

I have asked before, please find me any car sold in the US that ships with a copper plug. Besides Chrysler.


2007 Kia Rio5 with a L4 1.6 came with Champion copper plugs. The manual lists NGK or Champion (both copper) part numbers.

A friend's 2006.5 Kia Optima with a L4 2.4 came with Denso Iridiums, however.