Houston TX area G-owner as well with this same problem. Cold mornings and nights and it is scary loud and squeaky sound. I have 122k miles on my G and no more warranty. Has anyone else figured this out yet???

 

So if you follow the path of the serpentine belt then it’s a short list of things it could be:

1. The belt itself. Highly unlikely bc it’s new but keep in mind this new belt is tighter and shorter than old belt, therefore creating the noise. Move onto the next bullet below.
2. Idler pulleys - I don’t recall how many idler pulleys there are, but it could be 2 or 3. These are held on by a single bolt. They have bearings that wear over time and will squeal when cold and worn. A tighter belt will definitely add more noise in this serpentine path. These are cheap and easy to fix (<$20 and a single bolt). Try this replacement first.
3. Belt tensioner - 2nd least expensive, easily changed if you chg the idler pulleys. It is right in front of you. 1-2 bolts.
4. Power steering pump - more expensive than previous but could be a culprit
5. A/C pulley - prob the most expensive fix if this is going bad.
6. Crankshaft pulley - highly unlikely but never rule out.

This is the key post for the DIY’r: https://www.myg37.com/forums/d-i-y-i...an-09-g37.html

My guess to why it stopped making noise after filling it up is that the engine sat idle and warmed up the grease/bearings to stop the noise.

You’ll get it but I would start with replacing the idler pulleys and tensioner. <$150 if you DIY

 

Forgot the Alternator as being in the loop of the serpentine belt.

Also, here's the diagram of the components that will help things.

 

Thanks Petemo, I will definitely try the pulley's out first.

 

Any update on this?

Having the exact same issue and have a video if anyone wants to see. Mechanic is thinking starter, but wasn't able to reproduce yesterday. They will try again today

 

My car makes a similar sound, I've chalked it up to be the clutch release bearing, as the clutch begins to rotate.

To be noted: I did a power steering flush, and clutch fluid flush and I haven't heard that sound since. These were done approx 2000km ago.

 

So did anyone ever figure this out?

My car makes the same exact noise that is in the video. Typically only happens after the car has sat over night in the garage. There aren't any other strange noises happening at all other than that one and only for a split second after a cold start. I've attempted to pin point where the noise is coming from by having someone start the car several times while i listened with the hood up. After about 4-5 times of starting and shutting the car off, attempting to find the origin of the noise, it stops making it. This is why i'm having a hard time believing it could be the starter as some have suggested, and makes me question the pulleys. Seems like after a few times of starting, something warms up and the noise goes away.

I was thinking it could be either a idler pulley or maybe one of the pumps/compressors. Any new ideas? or has anyone solved their issue?