Help! S8 Scary Engine Noise...Worried

[Goran]

Originally Posted by steamship

Could it possibly be the engine block breather valve giving up the ghost?

I think you're onto something there! perhaps the rubber diaphragm has failed and is vibrating as it lets air out?

Its the black plastic UFO type object at the back of the engine.

Here it is in a picture I borrowed from another forum member's post as it shows the engine bay without covers.

It is easy to remove by jubilee clip or the Audi type clip, but I'm not sure if its safe to run the engine without it or with the rubber hose plugged to test if the noise stops?
Probably ok for a minute or two, as its just a sprung rubber diaphragm to let some crankcase pressure out when it builds up enough to be able to open the diaphragm.

This is how it looks inside:

http://forums.quattroworld.com/a8/threads/8649.phtml