Air conditioning intermittent "hiss"

Hi, I've searched for an answer to this one a number of times since this started happening last year. While on, my 2017 taco's AC makes what I can only describe as an intermittent "hiss" sound. It eases in and out. It's certainly noticeable, especially when the fans aren't maxed and the truck is stopped. The A/C blows reasonably cold (well... today it felt weak, but this noise has been happening for nearly a year and it was blowing cold all of last year. there may be two issues).

I must be describing this sound weirdly, as I haven't seen a single other mention or video of the same thing.

Here she is: https://www.youtube.com/shorts/jKh_ZoE0OU8

Any suggestions would be appreciated!

 

https://static.nhtsa.gov/odi/tsbs/2022/MC-10207964-9999.pdf

 

Ha! “Whistle.” Very likely it. Much appreciated!

 

I have this same noise. I am a tad over 36k miles so hopefully they still fix it.

 

That hiss is the AC expansion valve and gas expanding into the evaporator when the compressor kicks on. Normal operation.

 

THIS

Completely normal but often more noticeable if the charge is a little low since the system will cycle more.

 

Could this be a similar sound I’m hearing when I first start my 2023 when the ambient temp is high with ac on backing out of the driveway? After I back out and start driving it goes away and I never hear it again.

 

Could be but there's all sorts of other things happening in new vehicles automatically, air injection systems, blend doors moving, AC coming back up to high side pressure... etc