Metal noise R320

[FlavioM]

Hi guys, I've got a 2008 R320 with 105k miles.
In the last few months I noticed a noise coming from the engine when I accelerate. It's like a ticking noise, and it's more noticeable when I accelerate at low rpm. The noise sounds like this https://files.fm/u/3be7m7zqj. I did't give it too much attention.
However, a few days ago I did a strong acceleration from standstill and I suddendly heard a metallic noise coming from the left hand side. It was something like two or thee "clank clink clunks" and it was quite noisy. It did it again in the night, always during a strong accelaration.
So now I am a bit worried... Do you have any ideas on what it could be?

 

[Uncle Benz]

I can’t listen to your file for some reason, but would you liken it to a machine gun noise? The hyvo chain inside the transfer box is known to stretch and jump. I’ve replaced quite a few

 

[FlavioM]

Hi Uncle Benz, don't know what's wrong with the file. However yes, I would say that the noise I've been hearing for the last few months it's something like a machine gun noise, but much lighter.
The clunky sounds that I heard the other day on strong acceleration, though, were much louder. They stopped as soon as I reduced the pressure on the accelerator.

 

[Uncle Benz]

Could well be the chain then. Do a bit of googling, see if you can find a video clip of the sound

 

[FlavioM]

11 mar, 22.06.m4a

Visit this link to download: 11 mar, 22.06.m4a

files.fm

See if now it works.
If it actually was the chain, what would happen if I kept it like this? Does it get worse or can it live like this?

 

[Uncle Benz]

11 mar, 22.06.m4a

Visit this link to download: 11 mar, 22.06.m4a

files.fm

See if now it works.
If it actually was the chain, what would happen if I kept it like this? Does it get worse or can it live like this?

No, that doesn’t sound like the transfer box chain.
Sounds more like engine, possibly bottom end.