Good to know.On the VANOS repair site (Rajaie) posted this trick
"The crankcase vent valve and 4 associate hoses fail and cause a vacuum leak. The valve gets stuck open and the hoses crack. These last 70-120k miles and usually fail 80-90k miles. Here are a couple diagnoses.
At warm idle, place a small plastic freezer storage bag on its side over the oil fill hole. If the bag sits on top or gets slightly sucked in, ~1", the valve is good. If the bag gets significantly sucked in the hole the valve is stuck open and bad.
With the engine off and cold, carefully remove the hose at the valve cover front corner. Blow hard into the hole. You should hear oil bubbling in the oil pan. If you don't hear the bubbling the top or bottom hose is likely cracked. The bottom hose often breaks just below the valve connection. There can also be cracks in the other two hoses."
Dipstick housing represents crankcase prssure, so it is almost always high from blow-by combustion. The dipstick can never suck in.
Vacuum exist in the Intake Manifold only.
Wrong... Pull your dipstick with the engine running. There is vacuum. Pressure would cause the dipstick to shoot out.
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When a PCV system fails, usually it is from a clog ---> increased crankcase pressure ---> oil leak past the seal etc.
The video you posted above is from a different mode of failure: too much suction. Funny enough, this is exactly what you want in an M54 engine to reduce oil consumption.
The "BavarianE39 mod" is exactly that: creating a lot of suction to reduce oil loss from leaky piston rings.
This was from my 2001 530i, it had a failed CCV and the dipstick tube (original non-updated version) was clogged