Yes, I would expect OEM parts to be generally the best quality. That said, I buy plenty of after-market parts and have saved a ton of money. On coils, one of my OEM parts failed at ~200K miles. I bought a set of 6 coils for $60 on EBay (this was ~4-5 years ago). At the time a set of OEM coils would've cost 3-4X as much. After perhaps 2 years, one of them failed, so I simply popped on one of the remaining good OEM coils, which I'd kept just in case. Still working just fine. Same thing happened on my 335i, but the one new coil failed after less than a year. Since they had a one year warranty, I ended up getting all my money back, so free coils! I just keep a spare coil in the trunk, and always have tools in there anyway.

If reliability is more important than money, stick with genuine parts. If you are ok with the occasional failure, and want to save some money, go with after-market, at least on the parts that are not a huge hassle to replace on the road. Even with the odd failure here and there, my cars have never failed to get me home, except when something really catastrophic happened (like when the trans died in the 325i).

 

I don’t recommend buying anything aftermarket, especially sensors or any electrical part. You don’t need to buy genuine bmw brand tho. You can buy OE, it’s the same thing. BMW doesn’t make ignition coils, they get them from Delphi is the case of the e46. The Delphi coil is the same coil you get but with the bmw logo on it.
Buy OE...not OEM but OE. Here is a good read. I use fcp to determine who the Oe supplier is most of the time.

OE Academy | FCP Euro

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I don’t recommend buying anything aftermarket, especially sensors or any electrical part. You don’t need to buy genuine bmw brand tho. You can buy OE, it’s the same thing. BMW doesn’t make ignition coils, they get them from Delphi is the case of the e46. The Delphi coil is the same coil you get but with the bmw logo on it.
Buy OE...not OEM but OE. Here is a good read. I use fcp to determine who the Oe supplier is most of the time.

OE Academy | FCP Euro

Right that's exactly what I'm asking though. I've read some people claim that the EOM are actually not the same as OE. The OEM is the same spec but it might come from a different factory, or have gone through different quality controls.

I dunno. I wouldn't normally think about something like this, but the number of reviews on the OE coils that say "FAILED" is troubling.

 

Lots are heard about the coils but I believe on the m54 engine they are actually pretty reliable. I didn't have any failure neither on my previous car (210k, kilometers) neither in the current (150k) and in the previous car they were Bremi, which considered slightly inferior compared to bosch.
As for the oe vs oem I'd say they are definitely the same part but I would also assume that the oe bmw part has a more strict quality inspection. Still though, I would buy oem, especially in the cases you can actually buy the part from the same exact manufacturer. It's something like bmw oil vs castrol oil, etc.

 

I read the oe Delphi coils are pretty good. I’ve got 198k on my originals. I’m actually placing an order right now for new ones, I’m going with the Delphi.


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Everything manufactured item has a failure rate, even the space shuttle which has a very thorough Q/A department. What you should be looking at is the failure rate and not just number of failures. Many more OE parts are manufactured and sold compared to OEM. Naturally you will have more failures with OE parts than OEM since many more OE's are sold. In addition, you only hear about the failure but not so much the non-failures. Without knowing how many were manufactured and sold to calculate actual failure rate, often times it's just a guess.

 

You don't say which you have, but 'wrench' suggests the early coils.

On the early coils, I've never had a coil fail. I HAVE had the lower boot
(which has a resistor in it) fail. They're $5, for decent Bremi boots. Just
be careful, as some require a removable cap, which the standard EQP plugs no longer have.

For the later coils, the $20 RockAuto Bosch coils have lasted 50k so far.

t
carries a spare, as well.

 

there was actually a recall on the early coils so there goes your theory Genuine BMW part is the best choice (in this case). 😉
but yeah, use the part from the Original Equipment supplier. you don’t need it to say BMW on it. but same manufacturer is good. as mentioned, buy from FCP Euro, it’ll tell you who makes the part for BMW and they offer Lifetime warranty which is much longer than BMW Parts warranty.

 

214K miles on the original coils and counting.

When it's time to replace them, here is the Original Equipment Manufacturer (w/o the BMW roundel tax) option: BMW E46 3-Series Ignition Coil Kit By Eldor OEM 12138657273

 

I don't know what type of coils you have but I am selling Ignition coils (6) Bolt-in style. If you want them DM me.

E46 parts

I am selling M54B30 parts I will keep updating this thread and what is available. The parts are from the last 7 of VIN: KM00949 $190 VANOS - with 190k. I have not taken it apart to look at the condition on the inside or how good the seals are. I can replace the seals if you want me to. Extra...

www.e46fanatics.com

 

It depends. Our aftermarket coils, including the BMW applications, were wound and potted in the US up until a few years ago. They went through typical thermal cycle, duty, and vibration validation test requirements and met OE output requirements. The coils mfg has since been moved to our Poland plant because we could not compete on price with Chinese coils. We still can't compete on price even with Polish labor and make up the gap with most customers through warranty and customer service. In general, I'd say our aftermarket coils are pretty good and meet the needs of a daily driver. If you raise your rev limit and stick it in a race car, I wouldn't be willing to make the same claim.

Chinese coils are another story. Some are fine. Some don't work out of the box. They do zero validation testing and just mostly try to copy the design and hope for the best. These are the ones purchased by companies like Advance Auto, it's no secret that they shop strictly on price point. NAPA takes a different approach.

 

Well written & explained. Most of what you share is completely unknown to the layperson.
As I've mentioned before, CRP is about a 1/2 hr. away from me. I work on some of their vehicles. Talk with them constantly about product ideas they have and occasionally they bring products for me to Beta Test.

They strive for quality over price. Which is very difficult, in face of the lucrative Chinese price point.
There was a time when the "Echlin" (NAPA's best line of electrical parts) part was as good as genuine or even better. I'm not sure that still applies in the 21st. century?

 

Echlin is our (Standard Motor Products) brand. I have no way of knowing what electrical products are being shipped. Because we have complete catalog coverage in our sectors, some of the parts in the box are going to be resale (parts we buy and re-box). It is not always cost effective to tool up a low volume niche part. Sometimes the vendor is OE, like I've found with our a lot of E46 parts, sometimes not. Sensors are generally produced in one of our Mexico plants. We continue to win a lot of quality and delivery awards in our industry but I can really only speak to parts I've been in contact with.

 

85k on these Bosch coils

https://smile.amazon.com/gp/product/B001COAL20/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

 

BMW has migrated suppliers over time for the pencil coils, from Bosch to Delphi to currently Eldor. The form factor has been the same for years so their latest suppliers are the best.

I would buy Eldor R3516S00100