Hey!
Recently purchased XC90 2.5 T AWD 2006. Petrol. Automatic. 209 hp. Serviced regularly at Volvo workshop. 230000 km.

At start-up, especially after the engine is cold, a recurring rustling / snoring sound is heard when I put in reverse or drive and drive at low speed.
The sound disappears at a higher speed and when it is warmer.
Made a video on how it sounds. I put the phone on the wiper blade, started the engine, backed out of the garage, drove slowly to the parking lot and then back to the garage. The sound is clearly heard in the video when I accelerate a little about 20 seconds into the video and forward with about 5-10 seconds between the "snores".

What can it be?

 

 

Use your automotive stethoscope to find the noise - you can buy them for $5 here. (I see your location is Sweden) I would make sure the noise is not coming from inside the timing belt cover before you drive it - it gets very expensive when that belt comes off when you don't want it to.

Or the noise could be the serpentine belt tensioner flopping around.