Here a slight audio video of the rattle noise,,,,you might hear it at the end of the audio video 
Here’s a picture of inside the oil cap,,,,as you might be able to see is some metal flakes inside the oil,,,,,customer was complaining about a rattle noise heard during cold start,,,,,,on a 2014 328 N20 engine,,,,,I verified the rattle noise from the engine,,,,,so I removed the oil filter and noticed the metal flakes inside the oil cap,,,,,some other dealer just performed a oil service 3000miles ago,,,,,there was probably plenty of metal inside the oil filter and oil.
ouch, nasty noise… re; filers, dealer was changing my oil until i took it over at 30k, pulled off the filter and washed it out– filter was 80% clogged with gritty carbon,,(large tablespoon of shit ) filter had never been changed im sure.
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I’m sorry to here that the dealer did not change the oil.
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Is this normal? Is this just break-in metal flakes? What caused the rattle?
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We have found two differs thing that cause the metal flakes,,,,1 the timing chain rail going bad,,,,,2 rod bearing going bad,,,,we think it a rod bearing on this engine
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How could this have been prevented?
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There is no way to stop this,,,,,when the N20 motors came out,,,,they had 2 problem,,,,rod bearing and timing chain rail,,,,we saw a lot of rod bearing going bad in bran new engines with less then 20k miles,,,,,so there is no way to stop this from happening
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Was the rod bearing a problem in the 2015 (2014-06 production date) year model e84 n20 engine? I’ve got an e84 with 83k miles on it. I’m considering selling it while it’s running well.
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No the rod bearing were not a problem
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Andreas,
has nothing to do with topic but I don’t know where to post….
I forgot to thank you for setting me on the right track to removing side inner trunk cladding on my 7. Just got to it today and revealed my stereo amp. Thanks!
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Your welcome,,,,,glad I can help
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The N20 is notorious for being noisy. Any hints on how to differentiate normal engine noise to bad one?
On a cold start, mine sound like a diesel with a little metallic sound, stops after around 10 seconds.
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That metallic sound for the first 10 seconds is normal,,,,you will know when there’s a difference in engine noise,,,,it will be this abnormal noise that just doesn’t sound right
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>>will be this abnormal noise that just doesn’t sound right [bmwtechnician]
When it starts we pretty much know it is rod bearing or timing chain or oil pump chain or some similar expensive thing is about to fail. What is you advise, what would yo do, if this happens on a car what has no warranty (>50k ml)?
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I don’t know what you should due if your car is out of warranty and has a timing chain or rod bearing problem,,,,I don’t see that part of the business,,,,,I only see cars that are still under warranty coverage.,,,,,I get asked this question a lot about this problem,,,,it sucks ,,,,I wish I had a answer for everyone.
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Hi Andreas, thanks for all the helpful info on your blog. I just bought a 2011 X3 with the N52 engine…and 2 months into ownership I am experiencing this noise 😦 Have you come across rod knock or rod bearing failure on the N52s?
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I have seen it ,,,,but that was on a very high mileage engine,,,,rod knock or bearing noise is not a common noise on N52
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Hi. the car (320i with N20 engine) is in the garage, and from cold there is a very loud noise coming from the turbo, I think it’s related to the linkage from turbo, is this normal or is there a fault here? What is the likely cause and solution to this turbo fault if it is a fault?
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That’s normal operations during cold start.
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Thank you for responding appreciate it, the sound lasts about 30 seconds and then goes away. I think the vehicle engineer was even able to replicate the sound even with the engine off (by doing something physical to the relevant part), I was wondering could it be loose bolt inside the turbo causing that noise or is this normal ?
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I would really have to hear the noise to make sure,,,,but all N20 rattle during first cold start,,,that’s a common thing,,,you said the noise goes away after 30 seconds,,,,that’s normal,,,they all rattled
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hi, Lately I Have Been Hearing this rattle coming from the exhaust
i checked the car in many places and no errors at all , engine is running perfect nothing is effected by this issue and you can hear it only when i’m revving and after driving it minimum 20 minutes so at cold start when i rev the engine i cant hear anything
it’s very wired cause when i’m revving the engine after 20 minutes of driving you can hear it
but if i wait 5 minutes the rattle goes away and on cold start everything is just perfect also when driving i never hear anything
i will be so glad if you can help on this
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Is there a reason why newest n20’s are much quieter than older ones. My friend has a 14 428i and I have a 13 328i and they sound completely different. Both at 50k miles
Thanks for your time
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No there is no reason why your car sounds loader then your friends
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