Odd rattle in engine bay from low RPMs

[funker]

I noticed an odd noise coming from the engine bay the other day, ended up recording a quick video:

https://youtu.be/y4Cf5jevlQM

It appears to only happen on low RPMs, hitting anything above 2500 makes the odd rattle go away. Considering it's so loud and there have been no dash lights come on, I ran an OBD reader that worked to no avail as nothing came up. Has anyone heard something similar in their Z4 or know what it might be? Will be taking it into a shop once I can find one here on my college campus.

 

[Smartbear]

I wouldn’t be driving that until i found out what it was, could be a loose camchain etc.
Rob

 

[dhobbs]

Strut braces can come loose, good idea to check all bolts are tightened up.
Are the heat shield attached OK.
I had an issue with the exhaust bolts rusting through and the bracket rattling.

 

[Haro]

Sounds like the disa.

 

[funker]

Yup, checked the DISA valve and that was the issue! Replacement is on the way.

 

[colb]

So it was the infamous Clacking Disa Valve, a sure sign its failed. Using a Mechanics stethascope to pinpoint the noise or a screwdriver with the handle placed against the ear and the blade touching the suspect areas of the engine would hgave been an aid to diagnosing the problem. When they do fail they certainly make what is described as a clacking noise, its the valve flap dancing about inside that produces the clacking.