"repetitive rustling sound" - turned out to be a failing timing chain

[acideraser]

Hi All,

My 2011 E70 (3.0 xDrive, Feb 2011, 90k on the clock) started making a sort of "repetitive rustling sound". it appears when first start the car and goes away within first 5-10 minutes of driving, so I assume when engine / car warms up.
It's is there only while driving from 1000 revs and above and the higher revs - higher the sound repetitions.

I will post a video tomorrow to give an idea but at least wanted to know if someone experienced similar issues? Could this be a first sign of a need for belt replacement?

Oil replacement service is due in 1000 miles, so I was going to ask the guys to check this as well but worried if this is belt related issue should be addressed immediately?

[acideraser]

Only managed to upload video now, this how it sounds https://youtu.be/BSVEuMNh4cE

[AW8]

Check passenger seat occupation

[acideraser]

lol, not that sound, the one from engine 

[Alan Gunn]

No idea but it don't sound good to me.

[Riggie]

Any exhaust smell in the car?

[acideraser]

[quote="Riggie"]
Any exhaust smell in the car?
[/quote]

no not at all

it sounds like some rotating part is off balance but comes from the engine  :'(

[Riggie]

[quote="acideraser"]
[quote="Riggie"]
Any exhaust smell in the car?
[/quote]

no not at all

it sounds like some rotating part is off balance but comes from the engine  :'(
[/quote]

Might help to narrow it down by where it's coming from, left/right/front/back?  Can you do a video with the bonnet open. Any sign of smoke in the engine bay?

[acideraser]

no sign of the smoke or anything unusual.
will try to another video with the bonnet open today

[acideraser]

[quote="Riggie"]
Any exhaust smell in the car?
[/quote]

Hi Riggie, thanks for pointing out to exhaust. It appears that it is indeed coming from under the engine and seems exhaust related, not chain or belt as I have feared.
No smell in the car and did not see any smoke underneath though

[Riggie]

[quote="acideraser"]
[quote="Riggie"]
Any exhaust smell in the car?
[/quote]

Hi Riggie, thanks for pointing out to exhaust. It appears that it is indeed coming from under the engine and seems exhaust related, not chain or belt as I have feared.
No smell in the car and did not see any smoke underneath though
[/quote]

Have you had it looked at? It sounds to me like exhaust 'chuffing' through either a manifold crack or failed gasket etc. The only snag is you'd expect to smell exhaust and/or see exhaust smoke.

[acideraser]

Hoping it's a failed gasket not a crack.
We were away for holiday, now booked in for next week.

[acideraser]

Well, they listened to the engine and the video we made and are 97 percent sure it is a timing chain...
Waiting for a quote now ...

[X5Sport]

Ouch.  The chain is at the rear of the engine so everything has to come out to get the engine out.  Why BMW chose to put it at the rear on the N57 series I can’t say.  The M57 (it’s predecessor) is at the front.

Not heard of a timing chain issue with that engine yet so they had better be right given how much work is involved!

[AW8]

If you had described rattling sound I suspect somebody would have suggested exploring possible timing chain or tensioner issues. Sorry but I missed the video link post.

I also have not heard of this on other similar engined cars yet.

Perhaps someone ran it with wrong oil top up or at low level.

Timing chain, guides ancillaries & labour wont be cheap if job to be done properly. Ideally I would want to entrust the work to someone who has done the same job before on that engine. You may struggle to find someone so experienced & due to the rarity of the failure.

Sorry to learn of this.......tensioner failure caused me to reluctantly part with my V8 E53.