4.8is With Hissing Sound

[TerminatorX5]

hmmmm... are there any vacuum lines that you could see? hissing sound would suggest air being siphoned... but, no loss of performance?...

lets if anyone else can chime in...

[deanblue9]

Your assessment of the situation is the same as mine. I could hear but could not narrow down the location. I could hear it coming from the top of the engine. After removing the engine cover I clearly hear where the hissing sound was generating. But, I could not remove that long black rectangular cover to have full access to the hissing sound. It appears thag rectangular box covers all sorts of wiring. May just need to take a ride to my friend's shop to have all the proper tools to work.

[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.