Hello!

I experience a whinig noise when I'm pressing the throttle, and the AC is turned on. When I turn off the AC, the sound goes away after a few secound. Comes back when I turn it on. Anyone knows what this is?

Edit:

After watching a few youtube videos i'm guessing this is the sound of a failing alternator... So I guess it's time to start looking for a new one. Anyone knows if this is something I could try to replace myself?

Thanks!

 

When did you last have the air con serviced ? Normally this little whine is a signal that there isn't enough refrigerant in the system. When you turn the system off, the compressor stops compressing, so the whine disappears. When the system is charged fully, part of the charge is lubricant for the compressor. I had this whine start on the first X350 I owned, and a recharge cured it, as it did on the second X350. The second time I knew what the problem was, and took the car in straightaway.

 

Ah, thank you so much for you answer. Makes sence since the sound goes away when I turn the AC off. I guess this is a much cheaper and easyer job then replacing the altenator!

 

The system is set-up so that if the refrigerant all disappears, a pressure switch will detect this and shut the system to avoid compressor damage. The problem seems to be that when there is low refrigerant, the system keeps running, but over time if the whining is ignored, the compressor will eventually suffer damage. How long that takes is anybody's guess, I got mine fixed pretty soon after hearing the noise,

 

My local independent workshop had some free time yesterday so I dropped it off for AC service. There was supposed to be 600 something—gas, but there was only 300 in the car. They filled it up and the sound went away.

Thanks!