Spark plugs - is there something that will last past 30,000?

scoobysnax · **Posted:** Mon Aug 27, 2007 1:16 pm

Changing spark plugs ever 30,000 miles seems crazy to me, I don’t know there is any other car that has that requirement. So I have some questions:

Is there anther spark plug I can use as a replacement that will last longer? I’ve read advertisements of certain plugs that promise better mpg and an increase of hp too. I realize those changes will all be minimal but if I don’t need to change them every 30,000 miles I think that’s great.

Does anyone recommend a certain spark plug that works best in the Liberty? (Mine is a 2004 and it’s the 3.7L)

What happens if you go past the recommended 30,000 mile change point? Is it bad for the cylinders or the valves? Do you loose performance? Or do you just risk losing a cylinder if/when one or multiple spark plugs fail. Is it possible that the car could just die while on the highway b/c the spark plugs won’t work?

Next question. A local Strauss Auto Shop near me quoted around $150 to $175 to change all (6) spark plugs and the PCV value. I’m assuming they are doing it with stock parts but I thought that was a pretty fair price. My parents have used this shop in the past and they are happy with the work.

sleeve84028 · **Posted:** Mon Aug 27, 2007 1:22 pm

It's ~$50.00 for all 6 plugs depending on what brand you purchase. It takes about 1 hour to completly change them out and the PCV replacement takes less than 2 minutes. That local shop is charging you about $100.00 / hr for this job. You might as well do the change yourself on a Saturday morning and save the $100.00 to put towards something else.

There are other platinum plugs out there that will last longer... They'll cost more though. Right now, I'm trialing a set of Iridium plugs in my Liberty to see what they look like at the end of the next 2 years.

Leaving your current plugs in will effect:
Performance
Starting Time
MPG
Engine "smoothness"

tommudd · **Posted:** Mon Aug 27, 2007 1:57 pm

I change mine every 25000 or so and for 10/12 bucks and an hours time not a problem.
Some vehicles say you can run forever with them but in my book that is plain stupid and lazy on the owners part

tom said that blame him!!

tjkj2002 · **Posted:** Mon Aug 27, 2007 2:02 pm

Yes there are plugs that will last longer then 30,000,as long as they aren't made by champion or NGK.Autolite makes a nice double platinum plugs that will last some time,Denso makes some really good Iriduim plugs that should outlast your KJ but will cost about $13 each.Oh and stay away from anything +3 or +4 type plugs since you can't gap them and the othe 2-3 tips like to fall off and ruin a engine.

Guest · **Posted:** Mon Aug 27, 2007 2:09 pm

scoobysnax wrote:

Changing spark plugs ever 30,000 miles seems crazy to me, I don’t know there is any other car that has that requirement.

You must be pretty young! :wink:

scoobysnax · **Posted:** Mon Aug 27, 2007 2:12 pm

Wow. Looks like I am being overpriced. So here are the obvious questions to which I know nothing about:

How hard is it to change the plugs? Do I need a special tool or just a wrench?
Will I need to take anything else apart in order to reach the plugs? Especially anything with a gasket?

Once I have changed the plugs will the engine need a tune-up? I think I remember having to do a valve sync when I had a carbureted bike, this is a fuel injected engine but I still want to be sure.

If I do the plugs myself I’d like to also do the PCV valve. Is that something I can easily do or is there more too it?

Thanks again for all the input, this site is great and I really appreciate the help!

scoobysnax · **Posted:** Mon Aug 27, 2007 3:00 pm

I just called the dealer to see what they would charge me to change the spark plugs and the pcv valve just to see what they would say.

$300!

sleeve84028 · **Posted:** Mon Aug 27, 2007 3:10 pm

scoobysnax wrote:

Wow. Looks like I am being overpriced.

It's always cheaper to do something yourself. A huge plus of doing it yourself is the knowledge you gain in the exercise.

scoobysnax wrote:

How hard is it to change the plugs?

The KJ engine is really easy to work on. Even for a begineer you only need a few simple tools

1) A 3/8" socket wrench
2) A 6" extension
3) Small spark plug socket. IIRC it's 5/8"?
4) a 10mm deep well socket to remove the coil pack

scoobysnax wrote:

Will I need to take anything else apart in order to reach the plugs? Especially anything with a gasket?

There are detailed instructions on this board on how to change the plugs. No actual engine parts are removed, save for the ignition packs and the unpluging of each wire harness

scoobysnax wrote:

Once I have changed the plugs will the engine need a tune-up? I think I remember having to do a valve sync when I had a carbureted bike, this is a fuel injected engine but I still want to be sure.

No.

scoobysnax wrote:

If I do the plugs myself I’d like to also do the PCV valve. Is that something I can easily do or is there more too it?

It's a $3.99 part at the auto store. It mounts on the side of the oil filler neck. It just pulls out and you replace it with the new one... EASY PEASY

Edit: Aforementioned link to the thead on "how to change the spark plugs on the 3.7L" As a note: the thread asks you to drain the coolant - I was able to leave the degaus bottle unopened and just roped out of the way

chetos · **Posted:** Mon Aug 27, 2007 3:12 pm

changing spark plugs every 30000 isn't that bad. Just have the right tools and you can do it in under 2 hours and have spent less than $15.00 to do it. I thought it would be a pain in the stupid until I did it.

I just changed the rear brake pads today and did it in under an hour and a half. Of course I had my dad (ASE mechanic) to walk me through it but now I know that too.

scotrn · **Posted:** Mon Aug 27, 2007 3:31 pm

Changing plugs every 30,000 miles seems perfectly reasonable to me.......then again I also have a high-performance turbo'd race car that needs those $15 a piece plugs every 10,000 miles / 1 year (whichever comes first).

adamkrz · **Posted:** Mon Aug 27, 2007 3:33 pm

Changed my plugs out twice so far - first time 1 hour- second time 1/2 hour,Actually pretty easy compared to some other v6 or v8 engines.

Jeger · **Posted:** Mon Aug 27, 2007 3:37 pm

Dont forget antiseize... :wink:

I have done the job many times without it but one day its gonna catch up to me LOL

I dont have sparkplugs in my KJ but I use regular Bosch platinums in everything else I have ever owned. 50K is not an unreasonable distance to go on a nice set of plugs.....heck I have ran them for 100K in a toyota truck and they werent too bad off when I changed them.

tommudd · **Posted:** Mon Aug 27, 2007 3:40 pm

Yes the plugs are right on top basically so no reaching down under the maifolds somewhere :lol:

I was at a Goodyear store the other day and about fell over when the guy was paying for a tuneup and tire rotation on a Liberty.

NOW I know and respect mechanics a lot, did it for several years myself but some places really take advantage of unknowing people, so sites like this are great to help you understand what you can and can not do, but plugs are pretty easy!

Jeepjeepster · **Posted:** Mon Aug 27, 2007 5:13 pm

You think changing the spark plugs every 30k is crazy? Do you change the axle fluid every 12k, the tranny and tcase every 30k, AND change the spark plugs every 30k? I do!!!

Newzpix · **Joined:** Wed Aug 08, 2007 10:51 pm **Posts:** 18

KJpilot wrote:

scoobysnax wrote:

Changing spark plugs ever 30,000 miles seems crazy to me, I don’t know there is any other car that has that requirement.

You must be pretty young! :wink:

+1 LOL

I'm trying to remember how often I changed them on my 66 Mustang w / 289 V8 + points, distributor cap, rotor + set engine timing

chefdab · **Posted:** Tue Aug 28, 2007 2:45 pm

I did the plugs on mine and the hardest part was keeping the coolant overflow bottle out of the way. Well that and the fact that I forgot to plug one of the wires back in and got a check engine light and rough idle for my trouble. But that was an easy fix. I would also just use the same NGK plugs that it came with. No sense in spending all that extra money for the little gain you'll get from those fancy plugs.

Jeepjeepster · **Posted:** Tue Aug 28, 2007 3:07 pm

Ill probably go with the autolight platinums when the time comes. The price isnt much more so I dont see a use in not getting them.

Anyone have any reasons to stay with the NGK's?

tommudd · **Posted:** Tue Aug 28, 2007 4:52 pm

I have the autolite in mine now just put them in last week and doing good, have a 500 mile trip tomorrow evening so will keep you posted

dieselenthusiast · **Posted:** Tue Aug 28, 2007 7:43 pm

tommudd wrote:

I have the autolite in mine now just put them in last week and doing good, have a 500 mile trip tomorrow evening so will keep you posted

I used autolite platinums in my Tahoe a few years back and they seemed to do just fine. I'll probably go with the NGK Iridium IX Spark Plugs.

chefdab · **Posted:** Tue Aug 28, 2007 8:23 pm

Jeepjeepster wrote:

Ill probably go with the autolight platinums when the time comes. The price isnt much more so I dont see a use in not getting them.

Anyone have any reasons to stay with the NGK's?

They worked fine for the first 30,000 miles. And they are cheaper than those fancy iridium ones. It's not like the stock tires that sucked for 15k and HAD to be upgraded.

Spark plugs - is there something that will last past 30,000?

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