N57 40d - noisy timing chain or something else?

[wogboy_9000]

Hi everyone,

I current have an M57 E70, however saw a 2011 E70 LCI N57 today for sale.
It has some sort of engine noise, which to me sounds like a timing chain. It has a rough, hunting idle too and a hissing noise coming from the LHS of the engine bay.

Here are a few vids of a cold start and rev.
https://youtube.com/shorts/6xwqMz8kA9o?feature=share
https://youtube.com/shorts/EIgCeS8S3yE?feature=share
https://youtube.com/shorts/-w5DTTcvJHc?feature=share
https://youtube.com/shorts/FTxMv9zS650?feature=share

I ran ISTA+ and it threw a series of EGR related codes (https://ibb.co/vk0LNyd).
Could this noise all be EGR related? Seems unlikely, but thought I’d throw it out there.

Thanks in advance.