# 60K miles and iridium spark plugs



## Phagus (Aug 5, 2003)

replaced the four-ground original bosch spark plugs with NGK iridium plugs (BKR6EIX-11) at 60040 miles yesterday.
the original plugs were worn but still ok. however, with the new plugs the fuel economy improved dramatically (by almost 20% - that's no joke). it is better than it was when the truck was new. whether i would see the same effect with the new oem style plugs i do not know, but the previous sentence suggests that i might not.
surprisingly, the torques on the original plugs were very inconsistent (why? don't they have a torque wrench at the factory?).
so, if you see a decrease in fuel economy, you might want to replace the spark plugs. 
the job took an hour and a half. 
tools needed: 
5/8" spark plug socket
pivot ratchet drive (the pivot helps but is not necessary)
6" extension for the drive
pliers
the procedure in brief:
remove engine covers. 
in order to reach the rearmost plugs, the MAFs have be disconnected and left hanging aside and the air intake hoses have to be disconnected from the air filter housing (release the metal bracket with the pliers and pull the hose off). 
disconnect the coil's wires. 
pull the coils out and off the plugs (vw has a tool for this but it can be done by hands).
remove the plugs with the wrench.
replace the plugs and put together in the reverse order. observe the spark plug torque settings. if a torque wrench is not available, use the manufacturer suggested method of tightening.


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## Shaka (May 20, 2001)

*Re: 60K miles and iridium spark plugs (****us)*

I'm a big fan of NGK goods ... they make nice stuff. FWIW, did you happen to take any pics at 60k of the plugs? I'd love to see how "used and abused" they really look ... just for the sake of seeing it. My truck is at 30k and I was half-tempted to change the plugs now, since its a cheap item, great for economy as you said, and I drive rather hard.


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## Phagus (Aug 5, 2003)

*Re: 60K miles and iridium spark plugs (Shaka)*


_Quote, originally posted by *Shaka* »_I'm a big fan of NGK goods ... they make nice stuff. FWIW, did you happen to take any pics at 60k of the plugs? I'd love to see how "used and abused" they really look ... just for the sake of seeing it. My truck is at 30k and I was half-tempted to change the plugs now, since its a cheap item, great for economy as you said, and I drive rather hard.

will post a picture of the plugs tomorrow.


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## yugodutch (Aug 9, 2004)

Ever heard of a brand by the name of Denso for the spark plugs? Also, I have a V6. The plugs should be the same, yes?


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## Phagus (Aug 5, 2003)

*Re: (yugodutch)*


_Quote, originally posted by *yugodutch* »_Ever heard of a brand by the name of Denso for the spark plugs? Also, I have a V6. The plugs should be the same, yes?

i reckon you are joking about not knowing what Denso is.
V8 and V6 spark plugs are different.


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## Phagus (Aug 5, 2003)

*Re: 60K miles and iridium spark plugs (Shaka)*

these have 60K miles and almost 3 years on them








one of the plugs in the middle had some oil on it









Edit: new URL with photo



_Modified by ****us at 7:08 PM 8-22-2009_


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## spockcat (Jun 5, 2003)

*Re: 60K miles and iridium spark plugs (****us)*

The 5th and the 7th look a little dark. Perhaps you have a couple of weak rings.
Did the plugs you put in have quad electrodes?
ALSO: Did you gap them? Or don't new plugs need gapping anymore? If you did, where did you find the gap info?


_Modified by spockcat at 3:57 PM 4-18-2006_


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## Phagus (Aug 5, 2003)

*Re: 60K miles and iridium spark plugs (spockcat)*


_Quote, originally posted by *spockcat* »_The 5th and the 7th look a little dark. Perhaps you have a couple of weak rings.


man, this is not good. in my perception, the only bad thing was the oil on plug #5. 

_Quote, originally posted by *spockcat* »_
Did the plugs you put in have quad electrodes?


no.









_Quote, originally posted by *spockcat* »_
ALSO: Did you gap them? Or don't new plugs need gapping anymore? If you did, where did you find the gap info?

_Modified by spockcat at 3:57 PM 4-18-2006_

no gapping necessary as the plugs are pregapped.


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## Jimbuffalo (Sep 1, 2005)

*Re: 60K miles and iridium spark plugs (****us)*

run the new ones for a few thousand miles and pull numbers 2, 5, 7, 8 and compare at that time.


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## Phagus (Aug 5, 2003)

*Re: 60K miles and iridium spark plugs (Jimbuffalo)*


_Quote, originally posted by *Jimbuffalo* »_run the new ones for a few thousand miles and pull numbers 2, 5, 7, 8 and compare at that time.

i'll pull out the plugs in a month. 
what surprises me the most is the difference in torques on the original plugs.


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## Shaka (May 20, 2001)

*Re: 60K miles and iridium spark plugs (****us)*

Those OEM plugs actually have VW --AND-- Bosch logos on them -- crazy. I've never really noticed my VWs in the past having VW logos on the shank, curious.
As for the plus, I agree with spockcat, the oil and darkness of the 5th one is the only one that really sticks out to me. I'd check them again as mentioned by someone else, but if you dont have any issues with misfires, its prob nothing (hopefully) that'd I'd even begin to worry about in the short term.
You may find, however, going to a single electrode performs differently (and lasts shorter) than the 4-prong style. Only time for sure will tell ... and yeah, the torque taking them off is often different .. I've noticed that even one ones I myself put on .. strange.


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## Phagus (Aug 5, 2003)

*Re: 60K miles and iridium spark plugs (Shaka)*


_Quote, originally posted by *Shaka* »_Those OEM plugs actually have VW --AND-- Bosch logos on them -- crazy. I've never really noticed my VWs in the past having VW logos on the shank, curious.
As for the plus, I agree with spockcat, the oil and darkness of the 5th one is the only one that really sticks out to me. I'd check them again as mentioned by someone else, but if you dont have any issues with misfires, its prob nothing (hopefully) that'd I'd even begin to worry about in the short term.
You may find, however, going to a single electrode performs differently (and lasts shorter) than the 4-prong style. Only time for sure will tell ... and yeah, the torque taking them off is often different .. I've noticed that even one ones I myself put on .. strange.

thank you for the input.
the audi engine from which this vw engine was derived from uses a bosch plug with a different part number. it appears that bosch makes these plugs specifically for this engine. these plugs shold be available at autozone but they aren't. no over-the-counter bosch plugs will fit.
all NGK spark plugs for 4.2L V8 have the part numbers staring with BKR6E 
the ngk plug for the 3.2L v6 has the part number IZKR7B
about misfiring. i read some place that due to the strict emission regulations, 1% or greater of misfires should be reported by the engine electronic with a check engine light. therefore, i had less than 1% of misfires before even though the fuel economy was worse than it is now with the new plugs.


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## spockcat (Jun 5, 2003)

*Re: 60K miles and iridium spark plugs (****us)*

When you do take them out again, check the gap. Should be less than 1.1 mm according to Bentley. I would never put in a set of plugs without gapping them. At least that is the way we used to do it in the old days.


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## Shaka (May 20, 2001)

*Re: 60K miles and iridium spark plugs (****us)*

To spockcat, most new plugs these days come pre-gapped. But I'd still say ****us should have checked it to be safe, at least that is what I do. Check at least one or two to make sure the mfg pre-gapped accordingly.
To ****us, sounds good. Technically speaking you are probably fine with the single electrode setup, but I am a huge fan of the 4-elec on these newer vehicles. Gap errision and other buildup can cause issues, so its sort of like having 3 "backup" ways to ensure your spark plug doesnt foul, or at least as quickly.
You are right about the misfires, but even if it wasnt misfiring it could have been that some of the original plugs were over-gapped (some of that could be again gap erosion, etc) .. if that were the case misfires may not have been occuring, but gas-mileage could have been reduced because of the gap. Either way, I'd say you're probably all in the clear now .. 
BTW, that macro shot of the plugs is good .. dunno what sorta camera you use, but it takes good pics!


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## Phagus (Aug 5, 2003)

*Re: 60K miles and iridium spark plugs (spockcat)*


_Quote, originally posted by *spockcat* »_When you do take them out again, check the gap. Should be less than 1.1 mm according to Bentley. I would never put in a set of plugs without gapping them. At least that is the way we used to do it in the old days.









i checked the gap when i installed the plugs.







all gaps were identical or within my measurement error. this is a japanese product, so, presumably, they are identical within the factory error as well. 
the original gaps were much bigger as you can see in the photo (more than 2mm). dunno why. maybe, because of the plug construction with the protruding central electrode. the original bosch plugs are a piece of art though. all edges machined and stamped as if the plugs is something that you will be holding you your hand, akin a cigarette holder or glasses








however, as i understand the plugs have resistors in them, and it is a combination of the resistor and the gap that determines the firing voltage. so, presumably, the iridium plug with its shorter distance between the electrodes has a stronger resistor.


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## Phagus (Aug 5, 2003)

*Re: 60K miles and iridium spark plugs (Shaka)*


_Quote, originally posted by *Shaka* »_...
To ****us, sounds good. Technically speaking you are probably fine with the single electrode setup, but I am a huge fan of the 4-elec on these newer vehicles. Gap errision and other buildup can cause issues, so its sort of like having 3 "backup" ways to ensure your spark plug doesnt foul, or at least as quickly.
...
BTW, that macro shot of the plugs is good .. dunno what sorta camera you use, but it takes good pics!

no company makes 4-electrode iridium plugs.
the macroshot is made with a SONY DSC-W5 camera. imagine the shots i can produce with a proper camera (which i do not have)


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## spockcat (Jun 5, 2003)

*Re: 60K miles and iridium spark plugs (****us)*

One reason you check the gaps is in case the plug is dropped in the box the gap can be closed down, especially with the single electrode style of plug you used. 
It is hard to tell the exact gap from the photo but it does appear larger than the Bentley spec. As for the 1.1 mm spec, maybe Bentley is wrong.


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## Phagus (Aug 5, 2003)

*Re: 60K miles and iridium spark plugs (spockcat)*


_Quote, originally posted by *spockcat* »_One reason you check the gaps is in case the plug is dropped in the box the gap can be closed down, especially with the single electrode style of plug you used. 
It is hard to tell the exact gap from the photo but it does appear larger than the Bentley spec. As for the 1.1 mm spec, maybe Bentley is wrong.

1.1 mm is the factory spec for the ngk iridium plugs. the plug part number ends in "11", which stands for 1.1mm
in my bosch spark plug photo, 1.1mm about corresponds to the thickness of the insulator wall on the central electrode.


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## RHMMMM (Jul 25, 2006)

*Re: 60K miles and iridium spark plugs (****us)*

Was just curious - how are these plugs holding up for you?


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## clintjg (Apr 10, 2006)

*Re: 60K miles and iridium spark plugs (RHMMMM)*


_Quote, originally posted by *RHMMMM* »_Was just curious - how are these plugs holding up for you?

Ditto.


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## Bill 2158 (Nov 7, 2003)

*Re: 60K miles and iridium spark plugs (clintjg)*


_Quote, originally posted by *clintjg* »_
Ditto.









Same plus is the improved fuel economy holding up? Any rough MPG numbers?


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## Phagus (Aug 5, 2003)

*Re: 60K miles and iridium spark plugs (Bill 2158)*


_Quote, originally posted by *Bill 2158* »_
Same plus is the improved fuel economy holding up? Any rough MPG numbers?

I have put ~3000 miles on the new spark plugs. The mileage did improve compared to stock and it is still holding up. I'd say that the improvement is ~15% in the city and ~10% on the highway.
A couple of my stock plugs were a bit soiled and I was going to check the condition of the new plugs after ~3000 miles BUT I just bought a used jetta and it is keeping me busy - new brakes, fluids and such. Once i'm done with the urgent stuff on the jetta, I'll post a picture of the new plugs.


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## RHMMMM (Jul 25, 2006)

*Re: 60K miles and iridium spark plugs (****us)*

Also, why did you use the BKR6EIX-11, stock no. 3764 instead of the standard BKR6EIX, stock no. 6418 that pops up in the part number finder on the NGK website when you search for the Touareg plugs? What is the difference? What made you choose the other?


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## Phagus (Aug 5, 2003)

*Re: 60K miles and iridium spark plugs (RHMMMM)*


_Quote, originally posted by *RHMMMM* »_Also, why did you use the BKR6EIX-11, stock no. 3764 instead of the standard BKR6EIX, stock no. 6418 that pops up in the part number finder on the NGK website when you search for the Touareg plugs? What is the difference? What made you choose the other?

good question. i got the plugs from autozone or advance autoparts. this was the part number on their computer. i did not check the number afterwards.
BKR6EIX-11 is pregapped at 1.12 mm. BKR6EIX is pregapped at 0.76 mm. bentley manual says that the gap should be 1.1 mm. i am not sure how to measure the gap on the original plugs shown in the photo above but the insulator at the level of the electrodes is greater than 1mm thick and the air gap between the insulator and the electrodes is greater than 1mm.


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## clintjg (Apr 10, 2006)

*Re: 60K miles and iridium spark plugs (****us)*


_Quote, originally posted by *****us* »_
good question. i got the plugs from autozone or advance autoparts. this was the part number on their computer. i did not check the number afterwards.
BKR6EIX-11 is pregapped at 1.12 mm. BKR6EIX is pregapped at 0.76 mm. bentley manual says that the gap should be 1.1 mm. i am not sure how to measure the gap on the original plugs shown in the photo above but the insulator at the level of the electrodes is greater than 1mm thick and the air gap between the insulator and the electrodes is greater than 1mm.









Hmm I wonder what the difference is (other than gap) ... temp perhaps?


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## RHMMMM (Jul 25, 2006)

*Re: 60K miles and iridium spark plugs (clintjg)*

On NGK's page, it says the BKR6EIX is the match, but on Advance Auto's, it gives either as an option, along with a ton more that are gapped at 0.032". I just wouldn't want to get the wrong one, obviously. It boggles me why they offer both as an option, I thought the gapping was more crucial?


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## Phagus (Aug 5, 2003)

*Re: 60K miles and iridium spark plugs (RHMMMM)*


_Quote, originally posted by *RHMMMM* »_On NGK's page, it says the BKR6EIX is the match, but on Advance Auto's, it gives either as an option, along with a ton more that are gapped at 0.032". I just wouldn't want to get the wrong one, obviously. It boggles me why they offer both as an option, I thought the gapping was more crucial?

perhaps, any iridium plug of the BKR6EIX series between 0.032" and 0.044" can be used? the engine management computer is smart enough to adjust the firing time accordingly,.. perhaps???


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## flippedWarthog (May 2, 2006)

*Re: 60K miles and iridium spark plugs (****us)*


_Quote, originally posted by *****us* »_
all NGK spark plugs for 4.2L V8 have the part numbers staring with BKR6E 
the ngk plug for the 3.2L v6 has the part number IZKR7B


I just checked the ngk website, and I noticed that they claim the IZKR7B is the "OE" plug for the 3.2L v6. I wonder if they are implying that these plugs are used as OE plugs from vw or are they considered "OE" replacements? I see from the posts above that the v8 came with the bosch plugs, and I'm wondering if the v6 also comes with similar 4-prong bosch plugs or if the v6 does indeed come with ngks? I guess I could just pull one of mine to find out...


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## acbristol (Aug 11, 2003)

*Re: 60K miles and iridium spark plugs (****us)*

****us,got a few questions for you:
1. Now that you have a few more months/ miles driven, are your MPG results holding up? Still 10 to 20% better?
2. Did you do the 40,000 mile service, as VW recommends? If so the plugs should have been replaced as part of that package.
3. What led you or influenced your decision toward NGK Iridium?
My questions are based on a quest to increase my so-so MPG on my 2004 V8 T-Reg, I am close to 55,000 miles now and getting ready to take a 3,500 mile trip on the 1st of Sept. So you really caught my attention!
Besides, I always ran NGK's in my race cars, but that is ancient history now.


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## Phagus (Aug 5, 2003)

*Re: 60K miles and iridium spark plugs (acbristol)*


_Quote, originally posted by *acbristol* »_****us,got a few questions for you:
1. Now that you have a few more months/ miles driven, are your MPG results holding up? Still 10 to 20% better?
2. Did you do the 40,000 mile service, as VW recommends? If so the plugs should have been replaced as part of that package.
3. What led you or influenced your decision toward NGK Iridium?
My questions are based on a quest to increase my so-so MPG on my 2004 V8 T-Reg, I am close to 55,000 miles now and getting ready to take a 3,500 mile trip on the 1st of Sept. So you really caught my attention!
Besides, I always ran NGK's in my race cars, but that is ancient history now.









I have ~4000 miles on the iridium spark plugs now. Too lazy/busy pulling them out for inspection. The mileage improvement is still holding up. without air conditioning i am doing 15 MPG in the city. 
The recommended spark plug change interval is 60 K miles (check your manual - I am 100% sure). The bosch plugs are like new - NO WEAR at all after 60K miles. I could have cleaned them up and run for another 60K miles I guess. BTW, 40K miles change interval is for the V6, as far as I can remember.
Iridium tip plugs seems like a smart idea. The thin tip does create a more spatially uniform spark. not all engines can take advantage of this though. Fortunatley, ours can.
P.S. Denso makes iridium plugs for the Touareg but they are even more expensive than the NGK ones.


_Modified by ****us at 12:16 AM 8-16-2006_


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## acbristol (Aug 11, 2003)

*Re: 60K miles and iridium spark plugs (****us)*

Thanks for the info, I mentioned 40,000 miles because my local dealer installed 8-# 101-905-615-A plugs @ 22.87 a pop for a grand total of $182.24!


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## Phagus (Aug 5, 2003)

*Re: 60K miles and iridium spark plugs (acbristol)*


_Quote, originally posted by *acbristol* »_Thanks for the info, I mentioned 40,000 miles because my local dealer installed 8-# 101-905-615-A plugs @ 22.87 a pop for a grand total of $182.24!

this is the 4-electrode bosch sparkplug shown in my photo above (all 8 of them) and here:








this plug appears to be produced by bosch exclusively for the touareg and hence the price is so high. however, a more generic NGK plug works just as well. BTW, you can buy this plug online for $8.10 a piece:
http://rep.speedycarparts.com/...=true


_Modified by ****us at 12:02 AM 8-17-2006_


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## pfb (Nov 28, 2005)

*Re: 60K miles and iridium spark plugs (****us)*

I realize this thread is a few years old, but I'm resurrecting it as the best informational post on Touareg V8 spark plugs...
I just put a set of the BKR6EIX-11's in. Easy job once you get the hang of pulling off the engine covers and un-clipping the connectors from the coil towers. I didn't find it necessary to disconnect the MAF or any part of the intake plumbing using the right size socket extension. The only thing that needed to be removed in addition to the engine covers was a small bracket that is used to position the ball post that the engine cover clips to. Two 10mm bolts, easily accessed. It blocks the drivers-front spark plug hole.
I wrestled with whether to use the wider gaped BKR6EIX-11's or the standard BKR6EIX's, but in the end used the -11's.
The stock plugs at ~72K miles had good color and looked like they would have kept going for a while, but it is an easy enough job (about as easy as any V8 I've ever done, could probably do the whole job again in under 30 minutes...) and the plugs are cheap enough ($58 shipped from Amazon) that I would not hesitate to do them a bit early.
Engine seems to run a bit smoother. Will report back with any notable change in mileage.

_Modified by pfb at 1:29 PM 8-17-2009_


_Modified by pfb at 1:31 PM 8-17-2009_


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