I got some bad news for you.....yours is bad too.
I never had the howling before, just burning oil a start up really bad and no vacuum at the oil filler cap. I bought an aftermarket CCV from BavAuto thinking they sell good and quality parts. It failed within 2 days. It starting howling like crazy and I was actually getting positive pressure at the oil filler cap.
I bought a genuine BMW CCV (for about 30.00 more than the aftermarket) and it has been fine for almost 2 weeks. Sometimes you do get what you pay for.
On a positive note, doing it again should be faster.
As for it going away when you pull the dipstick, that is because yours failed differently. You are pulling too much vacuum and it is being released when you pull the dipstick.
See the threads regarding aftermarket CCV installation issues and how to test.