Hey guys, haven't posted here in a while.

Ever since I got my Z about 5-6 months ago I've been really annoyed with this specific sound whenever I start my car and it only occurs during the first 5-10 minutes.

So far it seems like it's only happening when the car is not driven over night.

The sound occurs at around 65km/h+ and it sounds like some kind of mechanical-like noise or almost like a satellite type of noise and it only lasts for about 5-10 minutes (which leads me to believe the cold may be causing it?)

Here is an example of the noise (before the singing starts):

http://youtube.com/watch?v=dpgAq579cRA

I know this isn't the best video but the noise of my car reminds me exactly of the noise in this video. Pay attention to the little 'beepy' satellite noise in the beginning. Now picture that noise mixed in with some mechanical-type moving-robot noises.

I hope my description of the noise might help a bit in diagnosing this problem.

***Summary***
-------------------------

1.Start car - idles at about 1700 rpm until the engine warms up.
2. I begin to drive; when I reach 65km/h+ the mechanical-satellite noise begins to sound for about 5-10 minutes. After this time it disappears.
3. If the car is not in use for 8-24 hours, the sound will return.

 

Oh yes, forgot to mention the sound sounds like it's coming from the passenger side of the car

 

I listened to your video and I think it's your solenoid valve. Get it replaced.