Unsettling N54 deceleration sound

[Holtdahooligan]

This is NOT wastegate rattle.

Guys, what is going on with my motor? I took my car to a local indy bimmer shop and even they couldn't figure it out. They removed the valve cover and said everything looked fine. No gold look to the cam ledges, chain was tight and guides in good shape.

This has been going on for about 6 months now. I haven't noticed any decrease in engine performance and haven't gotten a single code. I'm full bolt on with inlets and e60 MHD flash (09 135i MT).

It sounds like some kind of oil starvation/valve train wine and only happens on deceleration. It doesn't matter whether or not the oils hot or cold. Engine braking from any rpm over about 3k will cause this loud decel noise. No, this isn't wastegate rattle.

This first video is with the windows up and oil up to temp, replicating the sound once.
https://youtu.be/fJgnNP5YgWo

This second video is with the windows down, oil not fully warm and I'm able to replicate the noise twice.
https://youtu.be/KxfKdh-IStQ

I haven't found anything similar to this sound online and could really use some help. Does anyone have a clue what it could be? Thanks.

[ShocknAwe]

All I hear is a squeak sound. Could be a vacuum issue.

[Holtdahooligan]

Originally Posted by ShocknAwe

All I hear is a squeak sound. Could be a vacuum issue.

Squeak? You might be referring to the BOV purge or turbo spoil sound. I'm talking about the chain like chattering sound as the RPMS fall.

[ShocknAwe]

Originally Posted by Holtdahooligan

Squeak? You might be referring to the BOV purge or turbo spoil sound. I'm talking about the chain like chattering sound as the RPMS fall.

Hearing must be going then. Apologies.

Does it happen with accel or change at all with rpms?

[Holtdahooligan]

Originally Posted by ShocknAwe

Hearing must be going then. Apologies.

Does it happen with accel or change at all with rpms?

It does not happen during acceleration. The sound does appear to change pitch/ sound more repetitve the higher the rpms when decelerating.

[Holtdahooligan]

I also have an oil analysis which did show higher than average levels of Tin and Lead. This analysis was done at 101,256 miles with 2,233 miles on the oil.