# Which spark plugs do I use, Bosch or NGK?



## WAM (Jan 30, 2002)

Folks,

2001 E46 325i (M54B25), which spark plugs do you guys recommend, Bosch or NGK?

I am talking about the OEM plugs available from the dealer.

I have no idea what my factory plugs are, but both are good quality brands.

Any recommendations on where to buy these from, the stealer wants $14.59 for each plug, which is probably double the normal price.

Thanks


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## Kaz (Dec 21, 2001)

In my past experience with other cars, it's typically best to stick with whatever brand came with the car. Generally this meant NGK for Japanese and Bosch for German. Mixing these always gave my friends and I poor results.

But modern BMWs are an oddity in that they are German engines with NGK plugs (BKR6EQUP) from the factory. I've noticed recently that BMW is finally specifying a Bosch alternate (don't have the number offhand) for those who prefer Bosch.

I've seen the proper NGK for $9 or so, and would personally stick to that. Keep in mind that BMW specs the plugs for a 100k replacement interval, though I'd probably at least do a check at every Inspection II or so.


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## The HACK (Dec 19, 2001)

I've had bosch in my car and NGK in my wife's 323Ci and have had no decernable effect between the two.

The Bosch is about $1.50 cheaper than the NGK.


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## WAM (Jan 30, 2002)

I know they are supposed to be changed at 100K, I am approaching 38K, what do you think, should I change them?

My car is running fine, I'm just being anal about it.

I have seen posts where people have said that their plugs were in bad shape at about 60K, so I thought I would change early.

If NGK were OEM, then I would prefer to stick to them.


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## Kaz (Dec 21, 2001)

WAM said:


> I know they are supposed to be changed at 100K, I am approaching 38K, what do you think, should I change them?
> .


I say don't mess with the plugs if you don't need to. I'd take one out and examine it (there are pages out there that show you how to 'read' a plug) if you really want to do something. With the type of plugs and ignition system in these cars, as long as you run the motor pretty hard on occasion, the plugs will probably look barely-broken-in for at least 50-60k. Otherwise I'd save the time and money and leave em alone for another year or so.


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## The HACK (Dec 19, 2001)

Ditto what Kaz said. When I took out my plugs, they looked almost brand new, except the color is slightly off (they're not the bright, polished white that new platinum plugs look like). When I took the plugs out of my wife's car, it's got a good amount of GUNK on the tips of the plug and the discoloration is pretty bad.

Our driving style is slightly different. I let my car run up to redline about once or twice a month. I take it to driving schools. She's pretty much your average everyday driver wrt to throttle application.


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## SergioK (Aug 14, 2002)

WAM said:


> I know they are supposed to be changed at 100K, I am approaching 38K, what do you think, should I change them?
> 
> My car is running fine, I'm just being anal about it.
> 
> ...


I just changed my plugs at the 70k mark. I wish I had done it at the 50k mark though. There was a noticable difference in startup, the smoothness of the engine, and throttle response. As soon as I cranked the engine over I noticed this change.

Although the plugs looked to be in good condition and the car ran fine, I'm glad I changed them out.


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## Kaz (Dec 21, 2001)

Hmm, I'd have to see a new one but those center electrodes look pretty worn.


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## SergioK (Aug 14, 2002)

Kaz said:


> Hmm, I'd have to see a new one but those center electrodes look pretty worn.


The electrodes didn't appear to me to be that worn out from new... I did notice that the gap between the electrode and the insulator was more worn out though.

Pretty good for 70k miles and 20 track days. :dunno:


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## Raffi (May 18, 2002)

I changed mine at 30K. For $60, it's definitely worth the peace of mind for me.


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## Brashland (Nov 20, 2002)

I've heard about plugs getting fused to the engine when left in for 100k. Is this just a mechanic ghost story or what?


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## WAM (Jan 30, 2002)

Thanks for the info guys. 

I am leaning towards doing the plugs at 50K. That will be when I change my diff oil and manual transmission fluid for the second time.

What else would you guys recommend at 50K? Fuel filter, O2 sensors?


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## SergioK (Aug 14, 2002)

WAM said:


> Thanks for the info guys.
> 
> I am leaning towards doing the plugs at 50K. That will be when I change my diff oil and manual transmission fluid for the second time.
> 
> What else would you guys recommend at 50K? Fuel filter, O2 sensors?


Nah, don't change the O2 sensor... that should last up to 150k or longer. As for the fuel filter, yeah, definitely change it at the 50k mark. I changed mine at the 60k mark and wish I had done it sooner.

Are you going to be doing this work yourself? Or having a shop do it?


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## WAM (Jan 30, 2002)

sergiok said:


> Nah, don't change the O2 sensor... that should last up to 150k or longer. As for the fuel filter, yeah, definitely change it at the 50k mark. I changed mine at the 60k mark and wish I had done it sooner.
> 
> Are you going to be doing this work yourself? Or having a shop do it?


The plugs I will do myself, the other stuff I will probably get done by an independent mechanic, as I don't have any ramps and jackstands and living in an apartment means I would have to leave them in the garage where things get stolen.


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## The HACK (Dec 19, 2001)

Brashland said:


> I've heard about plugs getting fused to the engine when left in for 100k. Is this just a mechanic ghost story or what?


Fused? No. If the engine got hot enough to melt the plugs, it'll melt your cylinder blocks too.

It DID take significant more force to break the OEM plugs free. You're suppose to use copper based anti-seize on the threads of the plug so they don't seize up and make it impossible to take out.


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## tim330i (Dec 18, 2001)

besides plugs (maybe) and the fuel filter what else should be done at 50K?

Tim


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## The HACK (Dec 19, 2001)

tim330i said:


> besides plugs (maybe) and the fuel filter what else should be done at 50K?
> 
> Tim


I do brake flushes about once a year on my wife's car and every 6 month on mine...Usually by 50 K you would have had 1 factory flush (the interval is 2 years I believe).

Also, the radiator is supposed to be flushed every 4 years but I do it at the 60K mark just for fun. I believe the "microfilter" is supposed to be changed out ever 30K miles so you're close enough to warrant a new microfilter too.


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## SergioK (Aug 14, 2002)

The HACK said:


> Fused? No. If the engine got hot enough to melt the plugs, it'll melt your cylinder blocks too.
> 
> It DID take significant more force to break the OEM plugs free. You're suppose to use copper based anti-seize on the threads of the plug so they don't seize up and make it impossible to take out.


I have such crappy tools that I had to use my improvised 'breaker bar' (a piece of pipe that I slide on the end of the wrench) to break loose my plugs. I used the same anti-seize that I use on my brake pins for my StopTechs.


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## joea9146 (Jul 16, 2003)

Changing plugs at 100k and oil at 15k in my opinion is all marketing / sales hype. I change the oil Mobil1 about every 5k and change the plugs about every 30k.... its cheap maintenance items. Wiating 100k for changing plugs can cause problems as previously mentioned thay can be really tough to remove.


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## Hutchman (Jul 20, 2004)

SergioK said:


> I have such crappy tools that I had to use my improvised 'breaker bar' (a piece of pipe that I slide on the end of the wrench) to break loose my plugs. I used the same anti-seize that I use on my brake pins for my StopTechs.


I call that bar "The Negotiator."


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