amsnooze

can someone help me id part in the attached image inside the red box.

2004A8L

I replaced mine two weeks ago.

2004 A8L 4.2

audiusaparts.com
OIL/AIR SEPARATOR 077-103-245-B

amsnooze

i was adding washer fluid and happen to touch it and it started to make noise, ouch. I did manage to make the noise go away by adjusting it little, not sure if i need to replace it or leave it alone.

@ 2004A8L, why did you have to replace yours?

2004A8L

Started to be a little noisy, more / less when moved or touched

MP4.2+6.0

World's largest and most overpriced PCV valve. Yes, they can make noise and are then replaced. Variety of posts on it if you search.

dvs_dave

As others have said its the PCV valve. It's normal for it to make a low droning noise at idle. Touching it just damps out the vibration from the reed valve inside which is why it quietens down.

If it's making a loud honking noise, then it's time to replace it.

jlbell

This is probably my most favorite, memorable, and laughable problem. Was accelerating slightly hard then a quick lift off then quack! I never laughed so hard at a car problem! Best description of what it sounded like:

Jack88

That's hilarious. I'd have to fix it for safety reasons, I may hit something laughing at it.

richard-tx

Sometimes just removing the oil fill cap while the engine is idling will cause the PCV valve to honk.

BrianE

Hilarious! I could see you getting funny looks at traffic lights!