[mictang]

Hi all,
After reading some posts about the spark plugs for N52 and a few other sources, it’s been nothing but more confusing, but after some more research about the ignition coils and the spark plugs themselves, I think I might be onto something, please comment and share your thoughts/experiences.

So as many of you probably already knew there are three part numbers and different plugs for our N52 engines, me and my family happens to own two N52 cars production date 2007 and 2012 with N52B52 and N52B30 respectively. Here are the plug part #s: (ordered old to new)

12120032137 = NGK ILZFR6D11
12122158253 = NGK PLZFR6A11S
12120037663 = NGK LZFR6AP11GS

For the 2012 5 series it’s simple and clear, either Bosch or Delphi coils and latest plugs (12120037663 = NGK LZFR6AP11GS) works fine. But on my 325i, it’s was quite confusing at first with realoem specifying the second latest plugs (12122158253 = NGK PLZFR6A11S) only for the N52B25 and latest for others such as the 328i (not sure but something like that). I have since developed a theory that BMW updated the part #s for both cost and longevity purposes.

For those of you don’t want the full detail, my plan is to run either Bosch or Delphi coils with the second latest 12122158253 = NGK PLZFR6A11S plugs in my 325i and possibly in the 5er as well. I know it’s still what realoem calls for but the logic behind took my a lot of thinking and I feel worth sharing.

After most sources and even parts store such as ECS Tuning claiming all the plugs are interchangeable and some people simply say newest is the best but without actual data or justification, I got frustrated and finally found NGK.com (which is one of official distributors for NGK) had actually listed all of the specs and even service life data for the three plugs and they are the following:

12120032137 = NGK ILZFR6D11
Center electrode: iridium size: 0.6mm
Ground electrode: Platinum
Overall Height: JIS (53mm)
Longevity: 100k Miles

12122158253 = NGK PLZFR6A11S (up to 2009)
Center electrode: Platinum size: 1.0mm
Ground electrode: Platinum
Overall Height: ISO (50.5mm)
Longevity: 90k Miles

12120037663 = NGK LZFR6AP11GS (since 2013)
Center electrode: Platinum size: 1.0mm
Ground electrode: Nickel
Overall Height: ISO (50.5mm)
Longevity: 40k Miles

One of the first reasons I didn’t want to believe newest is the best was the older plugs are iridium rather than platinum, every source will tell you that iridium will last longer and cost more to make, but in reality the newest versions costs more to buy (twice as much in my location). Some said the old ones are cheap because they are being discontinued but it’s still being made, so I don’t think that’s the only reason.

But the two latter versions are indeed called “high power” whereas the oldest are not, and given their larger electrode size, that could be true. The two latter ones also share one more difference compared to the oldest one which is their overall height, which has something more to do with coil compatibility (more on that later).

Between the two later versions, PLZFR6A11S is sometimes called dual platinum with both electrodes and has longer service life compared to LZFR6AP11GS’s single platinum center electrode. BMW did specify a shorter spark plug replacement interval during the transition of the three different plugs so it’s reasonable for BMW to change to cheaper (to manufacture) plugs, but I don’t want to buy less expensive to make plugs with more of my own money!

See where I am going with this? New plugs are probably indeed high power but actually lasts less longer. And before I get to my final conclusion, there are the coils. I couldn’t find a good list from realoem so this is from etkbmw.com, but pretty sure it’s accurate:

1 12 13 8 616 153 current
2 12 13 7 594 937 04.02.2015
3 12 13 7 594 938 30.10.2013
4 12 13 1 712 219 13.02.2014

My 2007 325i came with the 219 Bosch coils and one went bad at 200k km (original part), replaced one with the 937, also Bosch, they have different looks. My family 5 series came with 937 factory (funny how that starts in 2015 but were in a 2012 car?), one were cracked and all 6 coils replaced with 153 Delphi coils (updated design with metal casing).

Now I did read some people had compatibility issues between 937 coils and oldest ILZFR6D11 plugs, which can be explained by the different overall height of the plugs, the later spark plugs were shorter and the 937 coils were probably updated accordingly (the 937 works in my car but I am replacing all with the 5 good 937s left from the 5 series as they were meant to be used with newer plugs which I plan on running). The 153 coils as far as I know were updated for longevity purpose and interchangeable with 937 as long as they are not mixed.

So here are my final conclusions:
“Power”: NGK LZFR6AP11GS = NGK PLZFR6A11S > NGK ILZFR6D11
Longevity: NGK ILZFR6D11 >= NGK PLZFR6A11S >> NGK LZFR6AP11GS
Usable Longevity: NGK ILZFR6D11 = NGK PLZFR6A11S > NGK LZFR6AP11GS

(I believe BMW reduced spark plug interval due to fouling and deposits, which was observed in the 5 series, the two longer lasting plugs probably needs replacing before the electrodes go out but will last longer than 40k Miles for sure)

(Oh and I don't really believe in more power per se but with similar usable life and price, I am willing to try it with BMW saying so)

Cost: NGK ILZFR6D11 <= NGK PLZFR6A11S << NGK LZFR6AP11GS
(specific to my location)

Coil compatibility:

Delphi 12138616153 = Bosch 12137594937 = NGK PLZFR6A11S = NGK LZFR6AP11GS (interchangeable in sets)
Bosch 12131712219 = ILZFR6D11 (outdated, both not compatible with above)


Final conclusion:
My personal choice is Bosch 937 with NGK PLZFR6A11S since the coils are free to me and plugs are cheaper and what realoem calls for. Might use the PLZFR6A11S in the 5 series just to see what happens, guess is no difference at all.

If money is no issue then best to go with Delphi 153 with either NGK PLZFR6A11S or NGK LZFR6AP11GS, the Delphi coil should be better quality than Bosch and two later spark plugs has better performance.

Thoughts, people?

[lowrydr310]

Originally Posted by mictang

Final conclusion:
My personal choice is Bosch 937 with NGK PLZFR6A11S since the coils are free to me and plugs are cheaper and what realoem calls for.

If money is no issue then best to go with Delphi 153 with either NGK PLZFR6A11S or NGK LZFR6AP11GS, the Delphi coil should be better quality than Bosch and two later spark plugs has better performance.

Thoughts, people?

Realoem lists the ILZFR6D11 or PLZFR6A11S for my 06 325 (US Market - that's a N52B30 engine in a 325i), however both of those also show as discontinued. The two options that aren't discontinued have BMW part numbers but no corresponding OEM info or model number (such as a Bosch, NGK, or Denso part number.) I personally use the NGK Iridium LFR6AIX11 in my car as that's what was specified by several local and online auto parts stores, and they work great. I like iridium plugs due to the longevity and the fact that they have resolved several starting issues on many single cylinder motorcycles of mine.

Realoem doesn't even list a Bosch coil for my car, there's only one option and that's the Delphi coil with BMW part number 12138616153, which is a Delphi GN10571 coil. From what I've read this is good because of the metal insulating sleeve, however it was $5 more than the Bosch 0221504470 (#00044) which is what I'm using now.

Where are you getting the "Bosch 937" information? The only thing I could find referencing a "937" coil was a BMW part number, and the image of that part looks like a Delphi coil.

[mictang]

Originally Posted by lowrydr310

Realoem lists the ILZFR6D11 or PLZFR6A11S for my 06 325 (US Market - that's a N52B30 engine in a 325i), however both of those also show as discontinued. The two options that aren't discontinued have BMW part numbers but no corresponding OEM info or model number (such as a Bosch, NGK, or Denso part number.) I personally use the NGK Iridium LFR6AIX11 in my car as that's what was specified by several local and online auto parts stores, and they work great. I like iridium plugs due to the longevity and the fact that they have resolved several starting issues on many single cylinder motorcycles of mine.

Realoem doesn't even list a Bosch coil for my car, there's only one option and that's the Delphi coil with BMW part number 12138616153, which is a Delphi GN10571 coil. From what I've read this is good because of the metal insulating sleeve, however it was $5 more than the Bosch 0221504470 (#00044) which is what I'm using now.

Where are you getting the "Bosch 937" information? The only thing I could find referencing a "937" coil was a BMW part number, and the image of that part looks like a Delphi coil.

937 is BMW part number and is Bosch 0221504470.

just took out all of my original 219 coils (to confirm my theory) and a couple of the rubber sleeves were peeling off so BMW definitely had a reason for updating the coils.

but even the 219 lasted 200k kms (125k mi) so you shouldn't need to worry about the coils anytime soon, just if anyone is replacing with a set they should go with the Delphi coils (which i did for my family's car).

I ended up installing all the leftover coils (Bosch 0221504470) and plugs (NGK LZFR6AP11GS) from the 5 series since they were just laying around (the plugs were replace when I was out of town and the shop was trying to chase down a rough idle, I said okay but keep the old ones I was sure they are okay, ended up the one cracked coil caused it). And vola, it works great, smooth idle and good acceleration. Guess I saved myself the price of one set of coils and half set of spark plugs (they have like half of usable life left when took out of the 5 series).

As for iridium plugs, seems like the ones you are going with has a lower listing price than the oem ones. I do agree with BMW's logic on using platinum plugs since they will be replaced before the plug's longevity ends due to fouling and such, but if it's cheaper to run iridium then why not. The ones you are using are ISO height so you are fine with the newer coils too. (I wouldn't mix JIS plugs with ISO coils or vice versa though, I compared them and there is a difference in installed coil height, may not seal properly)

Does your plugs make any difference on idle and acceleration, etc? I am guessing not, just same as before?

[nsjames]

I just ordered new plugs for my 08.

LFR6AIX-11
6619
Iridium
https://www.ngk.com/product.aspx?zpid=9871

That's what NGK says to put in a 2008 N52.
I've never had an issue using what the NGK guide recommends. They are ISO height, and I did replace the coils with Delphi when I first got the car.

[Fritzer]

Subbed!

I still have the same plugs I bought the car with @85,xxx miles and now I'm at 125,xxx. No idea when they were last changed, but they're still going strong... for now! I have a feeling that I might need to soon.

[nsjames]

worn plugs will kill coils.

[Savedamanualse90]

If you look up bmwdoctor on YouTube he just did a complete video on the correct plugs for the n52 Bmw’s. He use to be a bmw tech in Europe and stated many things about having the incorrect plugs can destroy you coil pack quicker and side the notorious Bmw n52 erratic idle problems, check it out! The correct plugs are the ones with 4 metals curves around the node.

[Efthreeoh]

Originally Posted by Savedamanualse90

If you look up bmwdoctor on YouTube he just did a complete video on the correct plugs for the n52 Bmw’s. He use to be a bmw tech in Europe and stated many things about having the incorrect plugs can destroy you coil pack quicker and side the notorious Bmw n52 erratic idle problems, check it out! The correct plugs are the ones with 4 metals curves around the node.

Well, here's the actual P/N shown for the spark plugs for the N52 from Realoem.com. It's a single-electrode design...

[Savedamanualse90]

Originally Posted by Efthreeoh

Well, here's the actual P/N shown for the spark plugs for the N52 from Realoem.com. It's a single-electrode design...

Originally Posted by Efthreeoh

Well, here's the actual P/N shown for the spark plugs for the N52 from Realoem.com. It's a single-electrode design...

I was having the same problem. I searched for n52 plugs and the 4 prong plugs are not compatible with our cars only z4 n52 models which is a bit confusing?!?! I'm still doing more research to confirm the facts... I'll update ASAP

[ctuna]

places like fcpeuro or pelican parts have compatibility searches.
Which returns two or three types that can be used. BMW wants
to charge you 20 bucks for the 10 or less double NGK double platinums.
You can get the irridiums for about 12 dollars each. Since the job
of putting them in is of more consideration the 8 to 12 dollars
a plug they cost.
By the way you don't need a special spark plug socket for the N52.

[Efthreeoh]

Originally Posted by Savedamanualse90

I was having the same problem. I searched for n52 plugs and the 4 prong plugs are not compatible with our cars only z4 n52 models which is a bit confusing?!?! I'm still doing more research to confirm the facts... I'll update ASAP

I'm not sure how you are getting this confused, the N52 uses a single-electrode spark plug regardless of chassis application. I have a 2006 E90 325i and a 2008 Z4 3.0si Coupe. Both engines are N52, the E90 uses the lower power N52 and the Z4 uses the dual-DISA valve'd high horsepower version. Both engines use the same plug P/N.

[e90yyc]

I used the single-electrode NGK plugs whose P/N matches the OE plugs.

Never had any issues...

[Savedamanualse90]

Originally Posted by Efthreeoh

I'm not sure how you are getting this confused, the N52 uses a single-electrode spark plug regardless of chassis application. I have a 2006 E90 325i and a 2008 Z4 3.0si Coupe. Both engines are N52, the E90 uses the lower power N52 and the Z4 uses the dual-DISA valve'd high horsepower version. Both engines use the same plug P/N.

I was referring to these type of plugs. I've been using NGK but occasionally after replacing my maf, map, coils, spark plugs, manifold gaskets
And checking for leaks, my rpm still jumps up and down...

[The Nightman]

Originally Posted by Savedamanualse90

I was referring to these type of plugs. I've been using NGK but occasionally after replacing my maf, map, coils, spark plugs, manifold gaskets
And checking for leaks, my rpm still jumps up and down...

Do you have a part number? Realoem shows the same spark plug for the Z4 30i

https://www.realoem.com/bmw/enUS/sho...diagId=12_1417

12120037663, NGK LZFR6AP11GS

[nsjames]

Originally Posted by Savedamanualse90

I was referring to these type of plugs. I've been using NGK but occasionally after replacing my maf, map, coils, spark plugs, manifold gaskets
And checking for leaks, my rpm still jumps up and down...

did you attempt any diagnostics before replacing all that stuff, or did you parts shotgun it?

because single electrode NGK plugs have been working great in my junk for 45K miles.

I swapped them when I did the valve cover just because I was there, and the old plugs with 40K miles on them were still quite serviceable with a gap in spec.

so I'll just continue to use whatever NGK says to put in it.

[Savedamanualse90]

Originally Posted by freedomfries

Do you have a part number? Realoem shows the same spark plug for the Z4 30i

https://www.realoem.com/bmw/enUS/sho...diagId=12_1417

12120037663, NGK LZFR6AP11GS

I think Bmwdoctor on YouTube might be mistaken. I'm running into the same problem, the plugs are for n52 z4 only. I would agree this might be a dead end. Yes, I have diagnosed everything except a new valve cover since onetime last week I randomly heard a high pitch sound coming from my dash. This can only be one thing Pcv diaphragm on the clave cover . I've research this can lead to other minor oil leeks due to pressure in the engine from the vacuum leak.

[lche059]

Originally Posted by Savedamanualse90

I think Bmwdoctor on YouTube might be mistaken. I'm running into the same problem, the plugs are for n52 z4 only. I would agree this might be a dead end. Yes, I have diagnosed everything except a new valve cover since onetime last week I randomly heard a high pitch sound coming from my dash. This can only be one thing Pcv diaphragm on the clave cover . I've research this can lead to other minor oil leeks due to pressure in the engine from the vacuum leak.

don't think he's mistaken...
the car he's referencing is a 530i which uses n52b30 engine i believe. he said the 4-tip one works then obviously that's what he put in his car. maybe he's more up-to-date than realoem. if you watch his other videos, he did mention you need to do a firmware update to take advantage of the new plugs.

[cahme]

What I don't understand is that realoem.com shows a distinct change in spark plug at 12/2009, but no change in coil (?)
Does anyone know the why behind this?

I actually have a 10/2006 production Z4 with the 3.0si, but I swapped in a 2011 328i motor and kept my 3IM. I'm going with the LZFR6AP11GS (with Delphi coils).

[PhaseP]

Originally Posted by Savedamanualse90

If you look up bmwdoctor on YouTube he just did a complete video on the correct plugs for the n52 Bmw’s. He use to be a bmw tech in Europe and stated many things about having the incorrect plugs can destroy you coil pack quicker and side the notorious Bmw n52 erratic idle problems, check it out! The correct plugs are the ones with 4 metals curves around the node.

Don't believe everything you read or see on the internet
The dealership probably gave him wrong plugs
And all of those N52 spark plugs are "High Power", new, old, ancient, pre historic... see screen shot from Realoem.com

This is turning into one of those best engine oil threads. Just buy one of those listed follow the recommended replacement interval. Iridium's go 100Kmiles. I had Iridiums from factory with BMW and NGK part numbers on it. Replaced with NGK same part number around 60K miles, shouldn't have done that, since there was no wear on the electrodes yet. If the car sees 160K miles with me, I will replace Iridium NGK again. I don't have rough idle, only time I had it was due to bad MAF sensor electrical connection. 13 years and counting.

Issues such as rough idle, ain't going to be cured by different part number spark plugs. If you had worn plugs, replace them. If you don't have worn plugs, you have other issues.

[PhaseP]

Originally Posted by lche059

don't think he's mistaken...
the car he's referencing is a 530i which uses n52b30 engine i believe. he said the 4-tip one works then obviously that's what he put in his car. maybe he's more up-to-date than realoem. if you watch his other videos, he did mention you need to do a firmware update to take advantage of the new plugs.

n52b30 is what all the US E90 N52's are...

I looked a few videos and comments of this "bmw doctor", he has a lot of misinformation mixed up with correct information, some controversial, maybe intentionally maybe not.... Be aware.

[The Nightman]

I was curious what RealOEM showed for my 328i:
https://www.realoem.com/bmw/enUS/sho...diagId=12_1417

12120035915 - Spark plug, High Power, NGK PLZFR6A11S - to 01/08/2010
12120032138 - Spark plug, High Power, BOSCH FR7NPP332 - to 12/15/2009
12122158253 - Spark plug, High Power - from 09/01/2009

I replaced mine with the following:
12120037663 - Spark plug, High Power, NGK LZFR6AP11GS - from 12/01/2009

Curious what the rationale is behind all the different choices

NGK lifespan specs and materials:
"Laser Iridium" ILZFR6D11 100k miles (iridium center, platinum ground)
"Laser Platinum" PLZFR6A11S 90k miles (platinum center, platinum ground)
"Laser Platinum" LZFR6AP11GS 40k miles (platinum center, nickel ground)

[Efthreeoh]

Originally Posted by PhaseP

Don't believe everything you read or see on the internet
The dealership probably gave him wrong plugs
And all of those N52 spark plugs are "High Power", new, old, ancient, pre historic... see screen shot from Realoem.com

This is turning into one of those best engine oil threads. Just buy one of those listed follow the recommended replacement interval. Iridium's go 100Kmiles. I had Iridiums from factory with BMW and NGK part numbers on it. Replaced with NGK same part number around 60K miles, shouldn't have done that, since there was no wear on the electrodes yet. If the car sees 160K miles with me, I will replace Iridium NGK again. I don't have rough idle, only time I had it was due to bad MAF sensor electrical connection. 13 years and counting.

Issues such as rough idle, ain't going to be cured by different part number spark plugs. If you had worn plugs, replace them. If you don't have worn plugs, you have other issues.

Spot on.

The NGK PLZFR6A11S and Bosch FR7NPP332 are no longer in BMW's logistics system, but are still available in the aftermarket. In early December 2019, I bought and installed a brace of each; one set for the E90 and the other for the Z4.

The E90 was starting to misfire with 95,000 miles on Bosch plugs I sourced from BMW. The Z4 was just over 100,000 miles on it's original plugs, which were NGKs. I put the NGKs in the E90 and the Bosch in the Z4.