AC "pong" noise

[bimmerR75]

As best as I can describe it, when the AC is on, and clutch is engaged I get this whine that sounds like a "pong" game and it gets louder and higher pitch as the engine rpm rises. When I turn the AC off I have no sound whatsoever.

Anyone have any idea what this is? I just had the refridgerant refilled last week and the sound only started occurring after that.

1991 325i

[bimmerR75]

Figured this might help, pardon the bad view but you can clearly hear the noise as I accelerate.

Anyone have any idea if this is a belt or a compressor issue?

https://youtu.be/zukeilos5IQ

[bimmerR75]

Bump

[spike68]

Sounds like a bad compressor bearing.

[Das Delfin]

bad compressor clutch? Low on oil. Could be anything

[bimmerR75]

bad compressor clutch? Low on oil. Could be anything

Low on oil in the compressor or motor oil?
The noise seems to be intermittent, some days I can hear it, other days theres no noise. It typically tends to show up after I've been driving around all day.

[Das Delfin]

Compressor oil. Unfortunately there's no easy way to check as you'd have to empty the system completely and measure it. Take the belt off and see if the pulley is dirty or looks weird.

[bimmerR75]

Hm, I see. Just had the R134a flushed and refilled a few weeks ago, the sound didnt start until shortly after I did that. Wonder if that has anything to do with it, but I'll check the pulley. I am hoping if thats the case its not too difficult to get in there and swap that out.