A/C noise
 

Hi,

Does anybody recognise this noise?
https://youtu.be/h4Zwtg9ZB_o
The dealer has no idea whats causing the noise.
The system is vacumed and filled with 770gr gas.
The noise disapears when te AC is switched off.

What is done/new:
-new idler pulley
-new alternator bearings
-new serpentine belt and pulleys
-new distribution belt, and pump (twice)
-new powersteering pump + fluid
-new engine mounts
-new ac compressor
-new condensor
-new pressure sensor (AC circuit)
-new expansion valve

Everything looks right, hp pressure seems ok, no errors in vida.
Just that noise that is going up/down with the revs.
It seems that the noise enter the cars interior through te presurelines and the evaporator.

The car is a my2009 v70III, 2.4d

Anybody an other idea? :confused_smile:

No idea what it is but I have a similar noise! Does it stop when you turn the a/c off? I have assumed that it is a bearing somewhere......

I had the same noise after fitting a new compressor. the clutch on the original one seized which is a common issue. I had a local company who I know to be very good fit an OEM one and I was left with this noise. He thought it was due to low gas but the levels were correct and trying to over fill it didn’t help neither did a second compressor. Ended up living with it as car was due to be upgraded.

The noise disappears when the AC is turned off.
I don't really think it's a bearing issue, my personal thought after changing all the parts that i mentioned above is that something is resonating.
I really don't have any idea where I can find the solution. I've spent hours and hours searching for something that I can't find.

It's a Volvo!
Likewise mine whines, up and down with the revs, so it is obviously from the a/c mechanical system and is speed related. Comes only with the a/c on. So either belt, clutch or a bearing. It does occasionally stop but only for a short while.
Very odd.

I replaced all that stuff, every bearing ( pulleys, idler, alternator bearings, powersteering pump, compressor, coolant pump, distribution pulleys etc.....)

Are you sure that's not the steering pump?
What colour is the power steering fluid?

When I bought the car (2 years ago), the power steering was filled with red colored fluid. Also the AC condensor had a leak. At first I repaired the condensor and the system was filled with gas -> The sound apeared.
A few days later I flushed the power steering system with new green fluid with the right specs (not original Volvo), I still had that noise. A day later I replaced the powersteering pump with a new one, and I replaced the alternator bearings, and fitted a new idler pulley, new tensioner and a new serpentine belt. Result was that I still had that noise. Two weaks later I fitted a new distribution kit and a new pump with the same result.
A year later I replaced the compressor with a new one, still no result

What about alternater? It's only obvious under the extra load from the a/c. A/c off, noise gone. A/c on, noise returns.

Alternator has new bearings, slip ring, regulator and brushes.