Bench test an AOS?

[patssle]

Some vacuum is normal on the oil fill cap. If you can test the pressure - normal is 5 inches. They say if AOS is bad then there is a ton of vacuum.

Also don't run the engine much if you can - they say too much oil coming from a failed AOS can ruin it.

[Gelbster]

In theory the vacuum is measured with a " slack tube manometer".
Perhaps someone has a diy? I found this but be careful you don't suck all the water into the engine!!!!
Homemade u-tube manometer - EcoRenovator
Here is the Pelican info:
Pelican Porsche Tech Article - Porsche 911 Air Oil Separator - Porsche 996 Carrera (1998-2005), Porsche 997 Carrera (2005-2008)