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Discussion Starter #1 (Edited)
I wanna change my spark plugs in my 08XK 3.7L. I was wondering what most people use or like(had best luck with). I did the search and got mixed answers and it was an older posts so was looking for a more up to date answers. I know that the XK can be sensative to non OME parts so I dont want to mess up my engine. I know it needs them because They havent been changed in a while and Im finding that the dealere I got them it through didnt do what they said they dis=d on inspecting the vehicle before the release to buyer. I just changed the air filter and it was soooooooo black and filled with those tree seeds I cleaned it out and put a new K&N in and made a huge difference lol. So now looking to do plugs. I f you do list a type would like to ask the specific part number as I would like to order them . I looked at NGK ones:
http://www.jegs.com/i/NGK-Spark-Plugs/739/ZFR6FIX-11/10002/-1?parentProductId=
but I am not sure there are different models and lengths
http://www.jegs.com/p/NGK-Spark-Plugs/NGK-Iridium-IX-Spark-Plugs/830899/10002/-1
so being somewhat mechanically illiterate (can change oil and filters never done plugs) I want to get the right parts.And the links I listed are examples I know I found cheaper elsewhere but was using it more for showing different measurements. Heres better price examples.
http://www.autozone.com/external-engine/spark-plug?cmpid=PS:1:1:21
thanks
 

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ZFR6F-11G (NGK) is the OEM plug. I don't know so much about the 6, but with how picky the 4.7 and 5.7 are, I would suggest sticking to original equipment. There is nothing to be gained by different spark plugs other than maintenance intervals.
 

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Discussion Starter #4
I am begining to think Chrysler made their vehicles to use mopar parts exclusively just to get you to buy thier expensive products lol, Instead of allowing you to choose the brand you want.
 

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I've had NGK (6441) ZFR6FIX-11 Iridium IX Spark Plug's for 10k miles. MPG improvement was significant, but I had OEM plugs with a gap waaay out of spec.

No issues with them.

I spent like $7 a plug maybe?

[ame]http://www.amazon.com/gp/product/B000COVMXI/ref=oh_aui_search_detailpage?ie=UTF8&psc=1[/ame]
 

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The copper champion plugs used in the 4.7 and 5.7 are available at any auto parts store and are some of the cheapest plugs around. Those NGKs are most likely standard stock at auto parts stores as well.

That said, I do think Chrysler vehicles use excessively proprietary fluids.
 

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I'm getting tired of replacing the OEM NGK V-Power spark plugs on our 3.7L every 30K miles.
At least when the air resonator box is removed, it gives me an opportunity to clean the dirty throttle body.

I do know the 3.7L and 4.7L are nearly identical in engine design.
 

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Im sorry, i posted earlier that autolite were the oem when in fact they are NGK. I'm also running the NGK iridium lX, not autolite. I've had them in since July 2010. will pull them spring to inspect and measure the gap. But honestly, the underpowered 3.7 with these plugs, CAI and synthetic oils isn't so lazy anymore.
 

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Federal Regs/Laws and Consumer Demand has resulted in vehicles with more and more advanced systems that push the edge of performance and engineering. Because of that, the demands on the fluid are higher than ever before. and the equipment will NOT survive using past fluids.

Chrysler is NOT the only manufacturer that specify newer, more specific, harder to find fluids.

Anti-Freeze is because of owners that never changed the anti-freeze in their vehicles and when they damaged the cooling system of their vehicles because of it, they blamed the manufacturers. That is why there is dozen new long life anti-freezes, when the old green is just fine, if people would just use it correctly.

Plugs, true, as long as you have the right type with the temp range, they should work just as fine. But people have experienced problems using anything but the specific OEM plug. Others have no problems at all.

You need to figure out the ignition scheme of your engine. Some engines that have the wasted spark system, usually have half the plugs on reverse current. If you reverse current on a spark plug, you reverse anode/cathode, on a single platinum plug, it will erode away even faster than a normal steel electrode plug. You need to use double platinum.
 

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Discussion Starter #10 (Edited)
So how would I find out what the temp plug I need or the ignition scheme? lol TY for the info..... and Mongo I agree with you on the fluids it just seems like they are making the vehicles more specific for everything so we can't take it to our normal mechanic if they arent trained on some of the ins and outs or quirks of the vehicle lol. I do feel proper maintenance will go a long way in max performance in vehicle without doing to many modifications. Simple stuff like synthetic oil change , oil and air filter changes(K&N), and proper air tire pressure , changing spark plugs or checking them every 30k. And I can do normal maintenance stuff but definitely cant do some of the mods or engine stuff but I was interested in trying to change the plugs if I can. Its why I was asking specific plugs. ...and ty for the many replies. I just wanna make sure I have the right plug. I understand the gaping Its just I saw there are some that are labeled different sides? Or did I read that wrong? As long as they are the right measurement and temp I should be fine. I also saw that certain plugs are a pain to change? Specifically the back ones? I have a feeling that these plugs are original and I worry that they will be tough to get out. My XK has 59500 miles on it for 08 so.......seeing that the air filter was never touched I'm pretty sure plugs haven't been. Seems like little care was done on this XK other than basic oil change according the to carfax report when I bought it.
 

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So how would I find out what the temp plug I need or the ignition scheme?
To find out the specifics of a plug, look it up from the Manufacturer Information, decode the part number/designation which varies by manufacturer. Or what most people do, is look up the recommended plug from the manufacturers catalogue.

What most people do, to avoid any problems is to use the exact OEM plug by Brand/Part Number in the O.M. or on a decal under the hood.

To find the ignition scheme, ummm, you look at your engine under the hood, read your O.M.. With the internet you can look up articles about the engine you have to learn even more. With the progress of engines, the ignition has become more precise and demanding as well. Most engines are Distributor-less Ignition Systems (DIS) today, if two plugs are driven by a single coil, likely one of the two plugs has the current flow reversed.
..... and Mongo I agree with you on the fluids it just seems like they are making the vehicles more specific for everything so we can't take it to our normal mechanic if they arent trained on some of the ins and outs or quirks of the vehicle lol.
In the 60's and 70's the manufacturers were producing only 2 or 3 car platforms at a time, the dozens of different models were just fender/grille/body changes. And everything was designed to be the cheapest easiest to produce, they used the same engine design for 30 years. Today we like our much more sophisticated and more specific cars, that is totally different from model to model, a new engine design every 3 years, safer and tons of extra safety equipment. A big part of that is because of Gov Regs/Laws, but Consumer demand as well; But everyone complains turns around and forgets that and complains why aren't their cars more universal and less specific?

Actually, if you were inside a Dealership Service department, the vast majority of them would horrify you. The techs are NOT well trained, that costs money that eats in to the insane profit margin they have, they are NOT well paid, and many Dealership policies designed to just get as many vehicles through the service doors and out to get an overpriced check, punish good mechanics doing the job right and reward bad mechanics taking shortcuts and doing a poor job. If they have any specific knowledge over an independent mechanic is because they work on a more limited pool of models and thus have less to learn.

This is NOT true of all Dealerships, but sadly it is true of many, even a majority.

The problem is the diagnostic and repair information and tools the manufacturers keep proprietary and out of the hands of independent shops and diy'ers, to insulate the Dealers from competition and force owners into the dealerships instead of alternatives. Why should a Dealership invest in training it's tech's to be a better service center then the competition, when the manufacturer made it so that the owners have no other choice but to bring the vehicle to the dealership for service/diagnosis? The magical tool that can read all the codes and start all the service procedures on Chrysler Vehicles, is the wiTech. Its nothing more than a cheap laptop with a cable that connects to the OBDII connector in the car and talks to it. The software is simple, any software company could make it cheaply and easily, they just need to know the protocols to be able to talk to the vehicle, which the manufacturers won't give up. Oh, you can buy the tool, only by signing a contract and paying about $20k (but the dealership doesn't have to pay those prices) even then half the procedures require logging into a corporate database from a dealership and communicating over the internet, so the Dealer only has access.

You corner gas station mechanic is just as likely to be a better tech than a Dealership mechanic, he can't afford the outrageously priced diagnostic tools (and he would need a different one for every manufacturer) or their very few alternatives, nor have the access to run the diagnostic and perform the procedure. In fact, its becoming pretty common now a days for Independent shops to do most the work and have to take customer's vehicle to the dealership and pay them to finish with the diagnostic tool the independent shop doesn't have.
I do feel proper maintenance will go a long way in max performance in vehicle without doing to many modifications. Simple stuff like synthetic oil change , oil and air filter changes(K&N), and proper air tire pressure , changing spark plugs or checking them every 30k. And I can do normal maintenance stuff but definitely cant do some of the mods or engine stuff but I was interested in trying to change the plugs if I can. Its why I was asking specific plugs... ...and ty for the many replies. I just wanna make sure I have the right plug. I understand the gaping Its just I saw there are some that are labeled different sides? Or did I read that wrong? As long as they are the right measurement and temp I should be fine. I also saw that certain plugs are a pain to change? Specifically the back ones? I have a feeling that these plugs are original and I worry that they will be tough to get out. My XK has 59500 miles on it for 08 so.......seeing that the air filter was never touched I'm pretty sure plugs haven't been. Seems like little care was done on this XK other than basic oil change according the to carfax report when I bought it.
The Owners Manual (O.M.) will have all that information. Safest just to use the plug specifically recommended in the O.M. Some people use different and never have a problem, other do have problems.
 

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Sparks & plugs & wierd stuffs

So I put Bosch 4+ platinum plugs into the jeep and lo and behold. my jeep started stalling at low speeds. about 100k after the spark plug change. just long enough for the computer to adjust to the new plugs. I narrowed it down to low idle stalls on any type of load (ie AC starting) I could idle on a slope in 4 low and it wouldn't stall until I turned the AC on.

It cant be the plugs.... so I checked out the intake and everything it all seemed good. except the idle air control was a little sticky, cleaned it with some spray cleaners and then lubed it with WD40 and let it dry I had a few metal shaving come out of it. problem fixed at least for 3 months and it started again, so I changed the IAC out and no more problems.

Maybe I am lucky but the bosch plugs are working great, they greatly improved the acceleration and take off. they have been in for a year so far. But I did double check the fitment codes through 3 different sources to make sure they were the right ones. Bonus those plugs you do not have to gap.

but trust me, if I had issues still I would have switched immediately to the OEM plugs to rule those out, I hope to get 3 years out of the bosch plugs and that would not happen with OEM.
 

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...Maybe I am lucky but the bosch plugs are working great, they greatly improved the acceleration and take off. they have been in for a year so far. But I did double check the fitment codes through 3 different sources to make sure they were the right ones. Bonus those plugs you do not have to gap....
Keep in mind, old plugs will reduce engine power and mileage slowly as the plug detiorates, the owner will slowly become accustomed to the lower power and mileage. Then when they change the plugs with fresh ones, they instantly regain that lost power/mileage to their pleasant surprise. Any proper working plug would have regained the power/mileage.

The claims some companies make about their plugs making more power are bogus, they don't.

I think a lot of "I just changed the plugs but I still ignition problems" come from people gapping the plugs incorrectly. Probably using the $0.75 gapping tool sitting in a bucket at the auto store check out. The ones that look like a coin, with ramp going around them. They're made in china and have been measured to be way off, not to mention using a ramp to measure/adjust gap is just wrong.

Lots of other plugs come pre-gapped, the OEM NGK for my 2010 3.7L come pre-gapped. If the plug comes with a plastic/cardboard tube around the threads to protect the electrodes, that means its pre-gapped, so handling the box doesn't cause the electrode to hit a hard surface bending them slightly and change the gap. No tube that protects the electrodes, get a gapping tool and make sure you use the correct gap.

Honestly, different plugs that are applicable to your motor should work fine, we just see enough posts about it, that the conventional wisdom becomes that you're just safer using the exact OEM plugs. I'm glad the plugs you choose worked out for you.
 
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