The two may not be related, but I have an 06 E60 525i base model, I've been hearing a rattling sound that's gotten louder over time but it hasn't effected anything as far as I can tell, yet.
well I was changing my oil the other day and when I looked up beyond the drain plug, to the front right, like 9 inches away there's a big chunk of metal that was held on with big bolts and I believe one of the bolts broke off and so it's just nestled in and bouncing off the metal around it making the sound.
I felt all around it to find any pipes, tubing etc that could have fluid going to it, or any exposed gears or anything else and from what i can tell it's just a big chunk of metal... I am very confused as to what it is, thinking maybe transmission counter balance possibly?? I'm attaching pics for reference and would appreciate any guidance!

 

Stop driving the car immediately.

Those are the brackets for the engine mounts.

Put your VIN in Realoem.com and find your build date and search for "engine mount".

 

Here's one I found that you might find informative. There are probably better videos and/or threads on this. Also check bimmerfest.com.


BTW, if you are unaware, those bolts are aluminum. You cannot reuse any aluminum bolts. Of course, the broken ones need to be replaced. You must use a torque wrench with the aluminum bolts and most all of them also want an additional angle turn after the torque is reached. That is a torque-to-yield bolt and actually stretches the bolt for maximum strength, but makes it not able to be reused. You have to find the torque and angle values to use.

 

DISA Valve

 

Huh? Those photos are not the DISA valve. Sure, a going bad DISA valve can make noise, but this is clearly something broken on the chassis. And, the 2006 525i has no DISA valves.