If you mean the CCV mod by I did this, check your work, Lots of suction at the oil cap can be a symptom of CCV problem. The sound could also be a vacuum leak. A smoke test is the best way to see if that is the problem. Where is the noise coming from?

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X5 4.6 2002 Black Sap, Black interior. 2013 X5M Melbourne Red, Bamboo interior
Dallas