[buytamil]

Hi

I am planning to replace the spark plug in my N52 325xi 2006 (122,000 miles) . I pulled the plug and attached herewith the pic of it. Let me know whether these are original plugs or its already been replaced.


thanks

[S65Hunter]

I think the originals are Bosch but say BMW on them. On another note not to hijack your thread...but are NGK plugs good to use?

[buytamil]

Originally Posted by AlpineE93

I think the originals are Bosch but say BMW on them. On another note not to hijack your thread...but are NGK plugs good to use?

Doesnt say BMW anywhere. so its already replaced. I dont know whether to replace or not.

NGK (1208) iridium are good.

[desertman123]

Originally Posted by AlpineE93

I think the originals are Bosch but say BMW on them. On another note not to hijack your thread...but are NGK plugs good to use?

Originally Posted by buytamil

Doesnt say BMW anywhere. so its already replaced. I dont know whether to replace or not.

NGK (1208) iridium are good.

I've been running NGK 6619 for years no issue.

[buytamil]

Is the plug ok or need to replace ? I bought as a used car. so dont know when it was replaced. Pls advice

[Welcome to NBA Jam]

If you're not sure, go ahead and replace them. They're cheap.

[BMWinAZ]

Replace! NGK was OEM on at least some model years of N52s. My old ones were NGK and they were fine till I replaced them with NGKs at around 75k. New ones are also trouble free. I have heard that Bosch are not the best for the N52 (unsubstantiated though).

[Efthreeoh]

Originally Posted by Welcome to NBA Jam

If you're not sure, go ahead and replace them. They're cheap.

Especially since he has all the crap pulled off already to get at least one plug out....

OP, the '06 N52 interval is 100,000-mile replacement for spark plugs. The originals have the BMW roundel stamped on them and son't say "Iridium" or 'Platinum" on the ceramic. So odds are the plugs were replaced (or at least that one ). The '06 has a Conditioned-Based Service (CBS) system, which tracks the amount of miles remaining for various maintenance items (parts) in the car. The items tracked are spark plugs, cabin airfilter, brake pads, brake fluid changes, and the engine oil change interval. The CBS also tracks inspections for State safety inspections and emissions inspections.

If the spark plugs were replaced correctly, the technician should have reset the CBS for the 100,000 mile plug replacement interval, so all you need to do is simply page through the CBS menu using the turn-signal stalk and see how many miles are left until the next plug change is scheduled. If the spark plugs were changed around 100,000 miles, then at 112,000 miles now on the engine the CBS should report 90,000 miles left until the next set are due.

But, since you've already pulled one out and are concerned that you don't know the maintenance history, you might as well just do the others at this point (and reset the CBS).

[buytamil]

Got the NGK plugs from Amazon. None of them are gapped to 0.044. Each one is different. Returning them. Where did you guys order the spark plugs ?

Thanks

[S65Hunter]

Originally Posted by buytamil

Got the NGK plugs from Amazon. None of them are gapped to 0.044. Each one is different. Returning them. Where did you guys order the spark plugs ?

Thanks

I got the NGK from amazon and they were all gapped perfectly.

[Efthreeoh]

Originally Posted by buytamil

Got the NGK plugs from Amazon. None of them are gapped to 0.044. Each one is different. Returning them. Where did you guys order the spark plugs ?

Thanks

You know you can gap the plugs with a 50 cent spark plug gap tool... There is no law that spark plugs come pre-gapped.

[Bimmer_Engineer]

Originally Posted by Efthreeoh

You know you can gap the plugs with a 50 cent spark plug gap tool... There is no law that spark plugs come pre-gapped.

I was thinking the same thing...I wonder if they covered return shipping...

[Efthreeoh]

Originally Posted by Bimmer_Engineer

I was thinking the same thing...I wonder if they covered return shipping...

I just changed the spark plugs on my GM 5.3L small block last Saturday. I used AC Delco "professional" series spark plugs I bought from a GM dealership that I bought probably a year ago. The gap is .040 inch. I checked the gap on all 8 plugs of course and a few were slightly under .040 inches, the others were spot on. I just adjusted the two that were under-gapped rather than freak out and think the entire set of plugs were defective...

For some reason, when a a person buys a BMW, he becomes OCD to the point he is nearly dysfunctional. I used to find it amusing; I am now starting to become concerned about it. I've named it Bmwitis.

[CTinline-six]

Originally Posted by Efthreeoh

I just changed the spark plugs on my GM 5.3L small block last Saturday. I used AC Delco "professional" series spark plugs I bought from a GM dealership that I bought probably a year ago. The gap is .040 inch. I checked the gap on all 8 plugs of course and a few were slightly under .040 inches, the others were spot on. I just adjusted the two that were under-gapped rather than freak out and think the entire set of plugs were defective...

For some reason, when a a person buys a BMW, he becomes OCD to the point he is nearly dysfunctional. I used to find it amusing; I am now starting to become concerned about it. I've named it Bmwitis.

I just changed the plugs + coils after I had a coil fail on my 328i. I didn't gap the plugs I just threw them in. They are NGKs and they "looked" fine.

[hassmaschine]

Originally Posted by Efthreeoh

I just changed the spark plugs on my GM 5.3L small block last Saturday. I used AC Delco "professional" series spark plugs I bought from a GM dealership that I bought probably a year ago. The gap is .040 inch. I checked the gap on all 8 plugs of course and a few were slightly under .040 inches, the others were spot on. I just adjusted the two that were under-gapped rather than freak out and think the entire set of plugs were defective...

For some reason, when a a person buys a BMW, he becomes OCD to the point he is nearly dysfunctional. I used to find it amusing; I am now starting to become concerned about it. I've named it Bmwitis.

lol. It's a total crippling of the hands and brain... May cause seizures, blindness, and paying thousands too much for simple repairs.

The only plugs you can't easily gap are the multiple prong ones.

[gbalthrop]

Originally Posted by Efthreeoh

...The gap is .040 inch...a few were slightly under .040 inches, the others were spot on. I just adjusted the two that were under-gapped rather than freak out and think the entire set of plugs were defective...For some reason, when a a person buys a BMW, he becomes OCD to the point he is nearly dysfunctional.

OP: please measure the gap of the plugs you removed, and report the gap range, as well as MINIMUM mileage on those plugs (miles during your ownership). Anyone who has actually recorded that information on their N52 engine, please also report. See my report below.

NOBODY has mentioned the biggest reason for changing plugs on the N52 engine (at least my theory -- which I would welcome any questions/ criticism about ;-): Enlarged Plug Gap which causes Misfire at High Load/ High RPM

1) Original specified plug gap is .040"
2) At 2,400 RPM, 60 MPH, one mile per minute, each plug fires ~1200 times/mile
3) In 50,000 miles at that rate (NOT counting explosions occurring in cylinders while standing/ stopped ;-) each plug has fired 60 million times (1,200x50,000)
4) 60,000,000 explosions have caused the plug gap to increase from .040" to >.050"
5) at ~ .055" the coils can no longer provide enough voltage fast enough to produce a reliable spark at high load (hard acceleration) and high RPM (>~5,000)
6) the SES lights and you experience rough running for ~ 60 seconds due to injector shutdown on one cylinder
7) you read codes and you have at least ONE of the misfire codes: P0301 - P0306
8) you remove your old plugs, and they look like those in the photos on this thread, showing NO fouling or electrode/ insulator damage, other than perhaps some wear-down of the center electrode, BUT the gaps are ALL now at least .050" and more likely, in the range of .055" to .060"

In the old days of leaded gas and low voltage ignition systems, where plugs in a high-compression engine would foul in several hundred miles of low-RPM operation, it was common practice for enthusiasts to remove, clean (sand/blaster plug cleaning machines were in most gas station bays), re-gap & re-install plugs every thousand miles or two.

Certainly do NOT recommend that approach on the N52 engine. If you are going to the trouble of removing the plugs, which you should NOT have to do more frequently than ~ every 50,000 miles, you might as well spend $8 per plug and install new ones.

Just ALWAYS measure the gap of the OLD plugs as well as the NEW, so you understand whether the concept expressed above is correct or not.

As for my own data point:
I bought my N52KP-engined 328xi nearly 2 years ago with 130,000 miles on odometer. It still looks and runs as new. About a week after I bought it, at WOT acceleration to ~6,000 RPM in 1st & 2nd, the SES came on accompanied by rough running (due to injector shutdown) for ~ 60 seconds after which the light went out and normal operation returned. This happened on 2 or 3 separate occasions within the next week. Code was read for misfire on cylinder #2 (P0302 | 29CE). Changed ALL plugs ($50 parts cost). Plugs removed, Bosch, most of which also said BMW, had gaps in the range of .055" to .060" -- NEVER had any SES light, rough running, or engine codes since plug change. NO other change or maintenance to cylinder #2 (misfiring cylinder).

George

[Delta0311]

At that mileage replace the coils as well

[S65Hunter]

Originally Posted by gbalthrop

OP: please measure the gap of the plugs you removed, and report the gap range, as well as MINIMUM mileage on those plugs (miles during your ownership). Anyone who has actually recorded that information on their N52 engine, please also report. See my report below.

NOBODY has mentioned the biggest reason for changing plugs on the N52 engine (at least my theory -- which I would welcome any questions/ criticism about ;-): Enlarged Plug Gap which causes Misfire at High Load/ High RPM

1) Original specified plug gap is .040"
2) At 2,400 RPM, 60 MPH, one mile per minute, each plug fires ~1200 times/mile
3) In 50,000 miles at that rate (NOT counting explosions occurring in cylinders while standing/ stopped ;-) each plug has fired 60 million times (1,200x50,000)
4) 60,000,000 explosions have caused the plug gap to increase from .040" to >.050"
5) at ~ .055" the coils can no longer provide enough voltage fast enough to produce a reliable spark at high load (hard acceleration) and high RPM (>~5,000)
6) the SES lights and you experience rough running for ~ 60 seconds due to injector shutdown on one cylinder
7) you read codes and you have at least ONE of the misfire codes: P0301 - P0306
8) you remove your old plugs, and they look like those in the photos on this thread, showing NO fouling or electrode/ insulator damage, other than perhaps some wear-down of the center electrode, BUT the gaps are ALL now at least .050" and more likely, in the range of .055" to .060"

In the old days of leaded gas and low voltage ignition systems, where plugs in a high-compression engine would foul in several hundred miles of low-RPM operation, it was common practice for enthusiasts to remove, clean (sand/blaster plug cleaning machines were in most gas station bays), re-gap & re-install plugs every thousand miles or two.

Certainly do NOT recommend that approach on the N52 engine. If you are going to the trouble of removing the plugs, which you should NOT have to do more frequently than ~ every 50,000 miles, you might as well spend $8 per plug and install new ones.

Just ALWAYS measure the gap of the OLD plugs as well as the NEW, so you understand whether the concept expressed above is correct or not.

As for my own data point:
I bought my N52KP-engined 328xi nearly 2 years ago with 130,000 miles on odometer. It still looks and runs as new. About a week after I bought it, at WOT acceleration to ~6,000 RPM in 1st & 2nd, the SES came on accompanied by rough running (due to injector shutdown) for ~ 60 seconds after which the light went out and normal operation returned. This happened on 2 or 3 separate occasions within the next week. Code was read for misfire on cylinder #2 (P0302 | 29CE). Changed ALL plugs ($50 parts cost). Plugs removed, Bosch, most of which also said BMW, had gaps in the range of .055" to .060" -- NEVER had any SES light, rough running, or engine codes since plug change. NO other change or maintenance to cylinder #2 (misfiring cylinder).

George

I just pulled out all my plugs on my N52 yesterday. All were just shy of .050. OEM plugs, 33K miles 10 years old.

[PhaseP]

Originally Posted by gbalthrop

:
I bought my N52KP-engined 328xi nearly 2 years ago with 130,000 miles on odometer. It still looks and runs as new. About a week after I bought it, at WOT acceleration to ~6,000 RPM in 1st & 2nd, the SES came on accompanied by rough running (due to injector shutdown) for ~ 60 seconds after which the light went out and normal operation returned. This happened on 2 or 3 separate occasions within the next week. Code was read for misfire on cylinder #2 (P0302 | 29CE). Changed ALL plugs ($50 parts cost). Plugs removed, Bosch, most of which also said BMW, had gaps in the range of .055" to .060" -- NEVER had any SES light, rough running, or engine codes since plug change. NO other change or maintenance to cylinder #2 (misfiring cylinder).

George

NGK Iridium ones are 100K miles. I don't know about the Bosch Platinum ones, I read some say 60K miles. Your car having 130K miles with BMW marked plugs were already long due for change regardless.

I had replaced mine that came with NGK Iridium from factory (BMW branded), with same NGK Iridium at 60K (without BMW branding on it). Now at 120K I replaced again; this time I was hesitant but went ahead with it. The plugs that came out had no visible wear signs on them. Measured the gaps and all six around had gaps 0.040~0.042 inches. So it was a waste of money and time, I would be better changing them after another 40K miles at 100K miles as the service interval says.

Again this is with NGK Iridium plugs. The Bosch or NGK platinum only plugs may have lower service life, or same, don't know.

[PhaseP]

Originally Posted by Efthreeoh

You know you can gap the plugs with a 50 cent spark plug gap tool... There is no law that spark plugs come pre-gapped.

NGK recommends not using the coin type tool to gap precious metal tipped plugs. They recommend using the wire feeler gauge tool for gapping:

[ctuna]

Mike Miller mentions one of the reasons for changing them early
is to avoid them being seized in place.

[hassmaschine]

Originally Posted by Delta0311

At that mileage replace the coils as well

No. Just, no. There's absolutely no reason to replace working coils. Replace them when they fail, nothing more. Unless you like burning money, which many in this community seem to enjoy.