Crankcase ventilation breather assembly oil leak

[ash2050]

My crankcase ventilation breather assembly is leaking oil.

Is there an oil seal behind it or does the whole thing need replacing?

Has anyone had this fail on them?

Don't like the look of taking it out!!

[UrS4boy]

AAN/ABY/ADU Positive Crankcase Ventilation (PCV) System with revised diagram, PNs and

My crankcase ventilation breather assembly is leaking oil.
Is there an oil seal behind it or does the whole thing need replacing? Has anyone had this fail on them? Don't like the look of taking it out!!

Why/where is it leaking? That is a oil vapour system so if you are seeing oil, something is clogged and the vapour is condensing to liquid before it is drawn into the MAF to Turbo hose (the way Audi intended).

I don't see an O-ring for item 23.

AAN/ABY/ADU Positive Crankcase Ventilation (PCV) System with revised diagram, PNs and Links: http://forums.quattroworld.com/s4s6/msgs/22506.phtml

[ash2050]

It's leaking from underneath the round ball (marked on pic).

Usually happens after the engine is switched off after a drive. you can see it weeping down through the bottom edge.

[saltinot]

The "ball is a press fit into the block. If that area has corrosion it might be the source. If you haven't already....spray down that area with brake cleaner (or equivalent) to clean it of oil and then drive your car a while and look again. If you start with it clean you can pinpoint your leak a little easier.

Based on my experience I would wager a bet that your leaking stems from two things.....the rubber hose getting old/soft and those awful one-time-use clamps that Audi loves to use. I would replace the rubber hoses with new ones and use proper hose clamps.

[popdemonic]

I had seen it weeping once on my old AAN but i would guess too much excessive blowby did it?