FWIW, I had virtually no oil loss for years, then last year I started to notice much oil use and was constantly having to add oil (2006 3.0 100k miles). Also, noticed much white goo under oil fill cap. I suspected the CCV after much reading. Replaced it this fall, and I am back to virtually no oil loss.

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2013 X5 35i MSport
2016 M235
2006 M3 ZCP