So this past week and up until now I've been hearing a weird noise coming from underneath my car when I have the clutch pressed in. It only happens during a cold start from what I noticed. Once I turn my car on and depress the clutch, at the moment of lifting my foot off the pedal I hear a noise as if someone is zipping something up. It's a zip like noise, I've taken a video of it just so it could be explained easier. After I let the car warm up, I press the clutch in again but this time the noise would stop. I doubt it's something wrong with my clutch as if it's slipping because it's perfectly fine. Clutch works great so I'm trying to figure out what's the problem. I've done some research and read about it probably being the Throwout Bearing but I'm just not 100% sure. Can anyone help me out here? Click the link for video...

 

I can't play your video from work, but what is the year and mileage?

 

It's an 03 and it currently has 104,600 miles.

 

I watched the video. That noise is abnormal. There's a buzzing mixed in there. A typical 350Z clutch should have a roller bearing noise, similar to the sound of a roller coaster's wheels on a track, but quieter.

Since the sound is synced with the engine RPM/idle, I can say with pretty good certainty that it's your throw-out bearing. Time for a new one, especially if you have an 03 with the original clutch/bearing, the bearing's grease has probably all dried up by now and it's grinding.

While you're getting that done, replace the clutch fork's pivot ball. Those are notorious for breaking on the 03 manuals. Also inspect your clutch slave cylinder, flex line, and clutch master cylinder, including your clutch fluid. Lastly, if you do drop your transmission, put in some new gear oil. I recently did a clutch job on my 06 with the CD009 gearbox, I put in fresh Redline MT85 and I've been very happy with the results.

Good Luck!
-Icer