Serious whine noise in engine bay
 

Hi guys so my wife’s car is a 2016 GT manual with just over 27000 miles and this morning out of nowhere it has started to make a very noticeable whining noise that gets louder and more noticeable under acceleration. It started on her way to work and I went and traded vehicles with her and drove it the short distance back to our house and I’m stumped on what the cause could be. I’ll try to include a link to a video I took of the car and see if anyone else has had this issue or recognizes the sound. Any help would be greatly appreciate. Also when I shut the car off and the motor is off there is something continuing the spin that is making a squeaking noise like an idler pulley or something.

Okay so after fiddling with some more things I can make the noise completely disappear and stop by turning off the AC. Turn it back on and the noise is right back, loud as ever. Turn it off and nothing. What could that mean?

One of three things. A/C compressor is failing, idler pulley bearing is worn out, tensioner pulley bearing is worn out.

I think the AC compressor is failing. It only makes the noise when the AC is on.

That would be the easy conclusion but, when the AC kicks on it puts an extra load on all the pulleys and bearings that are driven off the same belt, this includes the tensioner and idler pulleys.

Shut the car off, take the belt off and free spin the idler and tensioner pulleys and wiggle them to see if there is any play. you could also just take a listen with a mechanics stethoscope and put the probe on the pulley bolts to see if the sound is emanating from idler or tensioner pulley. If not, then it is the AC compressor or AC compressor clutch.

It’s at the dealership as we speak. The compressor failed, it’s being replaced under warranty. Sad that a car with 27k in mileage is already needing AC work

My Speed 3 needed one at 14,000. It happens.