Does my air conditioning compressor need replacement?

Ricochet J · 18 Jun 2016 at 13:33

I have a Megane III. It runs on a timing chain, and I believe there is also a regular rubber auxiliary belt driving the air con compressor.

When driving the car, there is a very strong and noticeable whirring noise. When I turn the air conditioning off on the climate control panel the strong whirring noise immediately stops.

The noise is not the air blowers, as when the air con is off, the and the blowers are still on, the whirring is not audible.

The whirring sounds unnatural to regular operation and I must deal with this. Is it likely the air con compressor is shafted? If it is, do I get the aux belt changed too?

mushtafa · 18 Jun 2016 at 14:13

Does sound like the noise is coming from the compressor, but it could be the belt or crank pulley. With the A/C on, it puts more load onto the pulley and belt system

Diagro · 18 Jun 2016 at 14:21

Does the ac work?

Might just be a worn pully.

go ask a garage to sound test them

acemastr · 18 Jun 2016 at 16:07

Compressors aren't on all the time, and definitely not when the ac is off. Could be the clutch making the noise though

Ricochet J · 18 Jun 2016 at 16:37

mushtafa said:
Does sound like the noise is coming from the compressor, but it could be the belt or crank pulley. With the A/C on, it puts more load onto the pulley and belt system

If I do get the compressor changed, I'll be getting the belt and crank pulley changed too. It makes sense that with the A/C on more load will be applied to the pulley.

Diagro said:
Does the ac work?

Might just be a worn pully.

go ask a garage to sound test them

The A/C works fine, with the caveat of the noticeable and very unnatural whirring noise. I'll drop into the garage on Monday. I wanted to get some opinions first.

acemastr said:
Compressors aren't on all the time, and definitely not when the ac is off. Could be the clutch making the noise though

It's not the clutch. The sound disappears completely when I switch the air con off. And the car's an automatic.

OpenToSuggestions · 18 Jun 2016 at 16:48

Ricochet J said:
It's not the clutch. The sound disappears completely when I switch the air con off. And the car's an automatic.

I think he means the clutch that engages the aircon compressor when you turn it on

.
When you turn it the engine ECU engages the aircon compressor (12v magnet) onto the pulley.

Ricochet J · 18 Jun 2016 at 16:54

I did not know that

mushtafa · 18 Jun 2016 at 19:08

OpenToSuggestions said:
I think he means the clutch that engages the aircon compressor when you turn it on .
When you turn it the engine ECU engages the aircon compressor (12v magnet) onto the pulley.

Not the same with the modern variable pumps. These run on the same drive system/pulley whether its on or off. The variable part of the pump changes internally to control the flow.

mushtafa · 18 Jun 2016 at 19:08

That didn't work, see here https://www.youtube.com/watch?v=DPuYF0eNK6M

acemastr · 18 Jun 2016 at 19:45

Ricochet J said:
If I do get the compressor changed, I'll be getting the belt and crank pulley changed too. It makes sense that with the A/C on more load will be applied to the pulley.

The A/C works fine, with the caveat of the noticeable and very unnatural whirring noise. I'll drop into the garage on Monday. I wanted to get some opinions first.

It's not the clutch. The sound disappears completely when I switch the air con off. And the car's an automatic.

Compressor clutch, not transmission clutch

Compressors click on and off all the time with a clutch.

PhillyDee · 19 Jun 2016 at 15:17

Usually the engine cooling fan comes on with the A/C, is it not that making the whirring?

Ricochet J · 19 Jun 2016 at 15:25

No it's not the cooling fan. After a long spirited run, when I switch the car off, I can the cooling fan remain on, and the noise of the cooling fan is quiet, barely audible, and a natural mechanical low amplitude humming.

The noise which I'm complaining about is an unnatural mechanical whirring noise.