How to know when to replace spark plugs

dannyjones · 05-02-2015, 09:29 AM

Hi all,

Quick question - how do you know when your spark plugs need replacing, without the obvious opening everything up and inspecting them?
I have some rough idle and long cranks occasionally and thought about replacing them, but an indy shop told me BMW should have done that already at 45k miles and I'm at 66k now. Is it true that BMW do it at 45k? I'm not the first owner so no idea how to find out if that was done or not.

Thinking of either replacing the plugs myself or getting the indy to do that and a walnut blast at the same time.

Thanks.

msjt · 05-02-2015, 09:30 AM

Just change them. They're cheap, especially if you're not sure if they've ever been changed before.

gtaccord · 05-02-2015, 10:44 AM

45k is bmw recommended interval for the n54.

Agentphish · 05-02-2015, 11:04 AM

Quote:

Originally Posted by gtaccord

45k is bmw recommended interval for the n54.

This. And look for your replacement plugs on eBay as a set. You should be able to get them cheaper.

galahad05 · 05-02-2015, 11:16 AM

Damn, reminds me that it's about time to change mine again.

335NJ · 05-02-2015, 11:32 AM

I just did mine, but on a tune it's every 20-25k, I don't drive very much, so I plan to just do them at 15-20k intervals since its $70 for piece of mind.

Delta0311 · 05-02-2015, 11:36 AM

Hit 40k a little while back and BMW did my spark plugs.

Miller335 · 05-02-2015, 11:47 AM

It's an inline engine, use it to your advantage.

dannyjones · 05-02-2015, 12:23 PM

Mine is an n55- is it the same 45k recommendation? And does that mean bmw would have done it for the original owner for free at that point or they just recommend you have it done?
I think I'll just do it, but would be nice to know if it was done or not.
Thanks all

335NJ · 05-02-2015, 12:46 PM

Quote:

Originally Posted by dannyjones

Mine is an n55- is it the same 45k recommendation? And does that mean bmw would have done it for the original owner for free at that point or they just recommend you have it done?
I think I'll just do it, but would be nice to know if it was done or not.
Thanks all

It's peace of mind, do them at 40k untuned, 20-25k tuned.

Also consider engine run time, meaning if you only drive 10 miles to work, but sit in traffic for 45 minutes, that is the same as driving more mileage.

Rossland · 05-02-2015, 04:34 PM

at 100,000 miles, the computer told me that I needed new plugs, but I ignored it because mileage had not changed, and the engine was running smoothly. At 135,000 miles, one of the coils failed, so I replaced all the coils and the plugs.

The OEM plugs are good quality and last a long time.

Delta0311 · 05-02-2015, 04:39 PM

Quote:

Originally Posted by Rossland

at 100,000 miles, the computer told me that I needed new plugs, but I ignored it because mileage had not changed, and the engine was running smoothly. At 135,000 miles, one of the coils failed, so I replaced all the coils and the plugs.

The OEM plugs are good quality and last a long time.

Intervals for NA and the turbo charged motors are not the same. I believe BMW NA spark plug change is around 80-100k miles on the turbo motors is every 40k.

gtaccord · 05-02-2015, 04:51 PM

45k.....

stieny · 05-02-2015, 05:52 PM

My cars at the dealer now for a water pump and thermostat...

My cars at 45k and plugs are coming up as part of the CBS service....all covered under warranty.

My car has the PPK1 installed so I'm not sure if that changes the parameters in the CBS system but I doubt it.

335e92tx · 05-03-2015, 08:28 AM

20k is a good rule of thumb (for modded motors that get leaned on). I notice a little misfire on some morning starts as it gets critical.

vapore0n · 05-04-2015, 07:34 AM

While the recommended interval is 45k miles, the included maintenance runs out just before it and dealers around here seem to not want to replace them at all.
My dealer hasnt replaced the sparks at all, even though I have the extended maintenance included. I havent complained about it because I already did them myself.

AllBlackBimmer · 05-04-2015, 07:40 AM

Quote:

Originally Posted by Rossland

at 100,000 miles, the computer told me that I needed new plugs, but I ignored it because mileage had not changed, and the engine was running smoothly. At 135,000 miles, one of the coils failed, so I replaced all the coils and the plugs.

The OEM plugs are good quality and last a long time.

What were your signs/symptoms of the failed coil?

Bavarian Tech · 05-04-2015, 08:59 AM

N52~SOP-3/09 100k
N51/N52 ~3/09- 60K
N54~ 45K
N55~ 60K

Douche · 05-04-2015, 09:15 AM

Quote:

Originally Posted by Bavarian Tech

N52~SOP-3/09 100k
N51/N52 ~3/09- 60K
N54~ 45K
N55~ 60K

What is this list?

#Tee · 05-04-2015, 09:17 AM

i dont play by the rules, did mine at 90k

Douche · 05-04-2015, 09:19 AM

Quote:

Originally Posted by AllBlackBimmer

Quote:

Originally Posted by Rossland

at 100,000 miles, the computer told me that I needed new plugs, but I ignored it because mileage had not changed, and the engine was running smoothly. At 135,000 miles, one of the coils failed, so I replaced all the coils and the plugs.

The OEM plugs are good quality and last a long time.

What were your signs/symptoms of the failed coil?

Same as a bad spark plug.

olivojoe · 05-04-2015, 09:36 AM

Quote:

Originally Posted by 335e92tx

20k is a good rule of thumb (for modded motors that get leaned on). I notice a little misfire on some morning starts as it gets critical.

+1

Tuned direct injection engines should be a ~20k to ~30k change interval. Not coming from me, but the guys at ProTuningFreaks, and everyone else that knows a lot more about these engines than I do.

05-02-2015, 09:29 AM	#1
dannyjones Lieutenant 82 Rep 405 Posts Drives: 2011 BMW 335i M-Sport Join Date: Jan 2014 Location: Florida, USA iTrader: (0)	How to know when to replace spark plugs Hi all, Quick question - how do you know when your spark plugs need replacing, without the obvious opening everything up and inspecting them? I have some rough idle and long cranks occasionally and thought about replacing them, but an indy shop told me BMW should have done that already at 45k miles and I'm at 66k now. Is it true that BMW do it at 45k? I'm not the first owner so no idea how to find out if that was done or not. Thinking of either replacing the plugs myself or getting the indy to do that and a walnut blast at the same time. Thanks.
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05-02-2015, 09:30 AM	#2
msjt First Lieutenant 160 Rep 305 Posts Drives: e92 335i Join Date: Jan 2013 Location: queens, nyc iTrader: (0)	Just change them. They're cheap, especially if you're not sure if they've ever been changed before.
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05-02-2015, 10:44 AM	#3
gtaccord Major 56 Rep 1,464 Posts Drives: 2009 BMW 335xi Join Date: Feb 2012 Location: Maryland iTrader: (7) Garage List 2009 BMW 335i xdrive [0.00]	45k is bmw recommended interval for the n54.
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05-02-2015, 11:16 AM	#5
galahad05 Brigadier General 158 Rep 3,158 Posts Drives: '07 335i e90 Join Date: Mar 2008 Location: Long Island NY iTrader: (0)	Damn, reminds me that it's about time to change mine again. __________________ Always do right. This will gratify some people and astonish the rest. --Mark Twain
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05-02-2015, 11:32 AM	#6
335NJ Colonel 533 Rep 2,872 Posts Drives: 2008 335i 6MT E90 Join Date: Feb 2014 Location: NJ/Philadelphia Suburbs iTrader: (1)	I just did mine, but on a tune it's every 20-25k, I don't drive very much, so I plan to just do them at 15-20k intervals since its $70 for piece of mind.
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05-02-2015, 11:36 AM	#7
Delta0311 Banned 7478 Rep 10,120 Posts Drives: 2011 BMW 335xi E92 2016 228xi Join Date: Apr 2009 Location: NJ iTrader: (1)	Hit 40k a little while back and BMW did my spark plugs.
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05-02-2015, 11:47 AM	#8
Miller335 Colonel 291 Rep 2,189 Posts Drives: 2007 E92 Join Date: Oct 2013 Location: Portland, OR iTrader: (0)	It's an inline engine, use it to your advantage. __________________ 2007 E92 335 6MT w/335is clutch FBO MHD E60 Wedge map 49k miles
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05-02-2015, 12:23 PM	#9
dannyjones Lieutenant 82 Rep 405 Posts Drives: 2011 BMW 335i M-Sport Join Date: Jan 2014 Location: Florida, USA iTrader: (0)	Mine is an n55- is it the same 45k recommendation? And does that mean bmw would have done it for the original owner for free at that point or they just recommend you have it done? I think I'll just do it, but would be nice to know if it was done or not. Thanks all
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05-02-2015, 04:34 PM	#11
Rossland Second Lieutenant 6 Rep 297 Posts Drives: US 06 330xi Join Date: Oct 2007 Location: Ontario iTrader: (0)	at 100,000 miles, the computer told me that I needed new plugs, but I ignored it because mileage had not changed, and the engine was running smoothly. At 135,000 miles, one of the coils failed, so I replaced all the coils and the plugs. The OEM plugs are good quality and last a long time.
	Appreciate 0 Quote

05-02-2015, 04:51 PM	#13
gtaccord Major 56 Rep 1,464 Posts Drives: 2009 BMW 335xi Join Date: Feb 2012 Location: Maryland iTrader: (7) Garage List 2009 BMW 335i xdrive [0.00]	45k.....
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05-02-2015, 05:52 PM	#14
stieny Private 4 Rep 81 Posts Drives: '11 335xi, M sport, 6MT Join Date: Feb 2014 Location: Pittsburgh, PA iTrader: (0)	My cars at the dealer now for a water pump and thermostat... My cars at 45k and plugs are coming up as part of the CBS service....all covered under warranty. My car has the PPK1 installed so I'm not sure if that changes the parameters in the CBS system but I doubt it.
	Appreciate 0 Quote

05-03-2015, 08:28 AM	#15
335e92tx ahat 1036 Rep 2,592 Posts Drives: Was '07-335e92 - Now '13-335IS Join Date: Mar 2008 Location: Texas iTrader: (6)	20k is a good rule of thumb (for modded motors that get leaned on). I notice a little misfire on some morning starts as it gets critical. __________________ '13 335IS N54 (1 of 373 LeMans Blue out of 3597 total production e92)- Grey interior (1 of 24 in LMB with any trans- 1 of 14 with DCT)-MODS -MFactory LSD/MHD-BQ custom Tune/ATM-IC/AFE Momentum GT Intake/Konis/Mfront&HeimJoint Rear rods&arms/Brembos. https://photos.app.goo.gl/Lo6aHZRo7XqtPkhL8
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05-04-2015, 07:34 AM	#16
vapore0n Captain 40 Rep 669 Posts Drives: 2010 335i Join Date: Jul 2011 Location: MA iTrader: (0)	While the recommended interval is 45k miles, the included maintenance runs out just before it and dealers around here seem to not want to replace them at all. My dealer hasnt replaced the sparks at all, even though I have the extended maintenance included. I havent complained about it because I already did them myself.
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05-04-2015, 08:59 AM	#18
Bavarian Tech Major 267 Rep 1,203 Posts Drives: 335i Join Date: Jan 2007 Location: Pittsburgh/Harrisburg iTrader: (15) Garage List 2006 330i [10.00]	N52~SOP-3/09 100k N51/N52 ~3/09- 60K N54~ 45K N55~ 60K
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05-04-2015, 09:17 AM	#20
#Tee Major General 557 Rep 5,367 Posts Drives: yes Join Date: Oct 2011 Location: Socal iTrader: (2)	i dont play by the rules, did mine at 90k __________________ You can follow my builds on IG: Tee212
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