Metallic noise with oil cap removed (v50 D5)
 

Removed my oil cap on my new v50 2008 with the engine running today. D5 180 manual.

This is what it sounds like. Is this normal?

https://youtube.com/shorts/YUxY7G6II8I?feature=share

Thanks

Normally its less metallic.... but if the vacuumpump has a leak in one of the hoses there is a popping noise...
What you can check and do is this: remove the oil fillercap with running engine.... remove the rubber hose of the vacuumpump (a cilinder on the side of the camshaftscover )and cover the hole airtight with your finger and observe the possible disappearance of the noise (or Not/less) try to record it and post it again.
If it disappears... try to find the leak... enginemounts/brakebooster or if you have a manual gearbox the egr warmup valve (this can be blocked off if its leaking)

Just listened to the noise and all sounds good until the cap is removed, what's the noise like when the engine is revved and cap is in place.

I now have a D5 S80 and the noise you have captured sounds normal, engine is quiet with the oil cap in place but metallic with the cap removed