I have a 2015 s60 T5 and I haven’t had any issues with it until 2 days ago I was driving back from the beach and there was a big storm in corpus.. the freeway was flooded and I drove through it. The next morning I noticed the car making this weird sound like a tuba being blown into for like a second but also far away? When I get close to the car it sounds like it’s coming from the back right side of the car. I’m not sure if water got into it or what but I’m super stressed since I have no idea what’s going on with the car or how bad things could get if I drive it. I’ve also noticed that the automatic stop and start isn’t working anymore, the car just stays running when I stop.

 

Also interesting. I have a similar problem

 

Im 99% sure my fuel line is clogged. Whenever I try to pump gas, it keeps stopping the pump. The tuba sound was air compressing in the tank. so it may be the same issue for you if it dounds like its coming from the tank or if you are experiencing the same things.

 

If you are having issues filling the tank, you may have an issue with the gas tank's evap system. The air is supposed to vent through the charcoal cannister and it sounds like that isn't happening, possibly due to a clogged vent / valve