Help! Grinding noise from my corolla 1.8 2015

[Fahad Ali]

The car starts perfectly fine on cold start but whenever it's started 30-40 minutes after the initial start this extremely weird grinding noise is heard.
Got it also checked from Toyota Dealership but nothing to avail.
Please help me! Drive is perfectly fine and smooth, fuel consumption is also great.
Car's driven 60k kms/ 37k miles.

Here's the video link of the stratup below

 

[Rock'n Roller]

Have someone else start it while you observe from under the hood. Need to narrow down the general location. Lots of possibilities. Maybe belt tensioner/belt, alternator, water pump bearing, A/C compressor, etc. Intermittent problems are the worst to diagnose.

 

[Fahad Ali]

Have someone else start it while you observe from under the hood. Need to narrow down the general location. Lots of possibilities. Maybe belt tensioner/belt, alternator, water pump bearing, A/C compressor, etc. Intermittent problems are the worst to diagnose.

Thanks for the input.
In my opinion I don't think there is any problem with any of the things you mentioned above since I got all of these diagnosed earlier.
This issue is not understanable to me at least.
Here I uploaded another video in which I press the accelerator as this weird sound is heard.

 

[Rock'n Roller]

Take the drive belt off and start it. This will eliminate all those components I mentioned.

 

[Fahad Ali]

Is it easily removable and reattachable since I've never touched those things?

 

[Rock'n Roller]

Could be challenging if your not mechanically inclined.

 

[JoshTRD]

i had a aratling noise and it turned out to be the exhaust pipe was touching up again another metal component.....it sounded horrible until i fixed it....maybe its that lol

 

[dfwkid]

If you remove the serpentine drive belt and start it, you will know immediately if it was any of those components. It's not impossible for the dealer to miss something