I recently noticed that my 2012 Buick LaCrosse (Eco) started to sound like airplane jet, when I accelerate (just pulling off to merging onto a freeway-it starts loud and gets louder, with any kind of acceleration). I noticed it a while back and just attributed the loudness, to the ECO system, now within a week a part, I had a member of my family and a friend, on separate occasions, both question why my 'car was so loud'. I've searched online and based on various comments I found it could be the wheel bearing, transmission, exhaust, battery cooling fan....the information is all over the place. Please help!!

Well, a wheel bearing sounds more like a growling noise....

Take it out on the road, and speed up to where the noise is loudest, usually around 40 mph....now safely, with no traffic around, steer slightly left, and then steer slightly right....if the noise, is slightly louder in one direction , and less when your steer lightly in the opposite direction, then that is usually a sign of a wheel bearing....

Wheel bearin was 1 of 6 possible reasons based on what I was able to locate online. Can you address the others I listed?

Sounding like an airplane? My only suggestion would be tht ur cooling fans are spinning quite fast...
If it were me thts where id start looking... An exhaust leak would be my 2nd suggestion.. But tht would b something much more able to pinpoint from the driver seat...

Might help if your able to record the sound and post it

If I understand the eco system on your car, it has a battery pack and a small electric motor to assist with acceleration. Just a shot in the dark here but possibly a bad bearing on the electric motor? I would take it to the dealer.

Sorry, I'm a little late to the game.

Does the noise increase with vehicle speed?

At speed, like 60MPH, (and in safe conditions) put the car in Neutral. Does the sound change?