4.8is With Hissing Sound

[deanblue9]

That's was my first assessment. But, could a vaccumm leak that high and far up inside the engine bay. The hissing sound is nowhere near the intake system. I have trying to get this resolved and really frustraded. Other than that, the x5 has been a great winter replacement while my M5 hibernate during the winter months.

[deanblue9]

I know for sure its not metal rubbing sounds. Like said, the hissing sounds only lasted for about 45 seconds to 1 minute; each hissing sound intervals would be maybe 5-10 seconds apart.