Air Con Makes Clunking Noise

[Guest benny147]

I have a citroen c3 desire 05 plate. Recently had air con serviced and now makes a loud clunking noise when air con switched , and also makes noise when running. Is this normal followng air con service? My Dad has c3 also and his makes no noise.

[paul.h]

The clunk noise should be from the compressor at the bottom right of the engine (looking from inside the car). This is normal and happens as the clutch on the compressor is pulled in so it runs. Should be happening frequently when the air con is on. You will also notice the engine fan will keep running to remove the heat from inside the car through the air con system. The noise on our C3 seems louder than on our other cars but could be due to being a small car and sat nearer the compressor or less soundproofing.

[Guest benny147]

The clunk noise should be from the compressor at the bottom right of the engine (looking from inside the car). This is normal and happens as the clutch on the compressor is pulled in so it runs. Should be happening frequently when the air con is on. You will also notice the engine fan will keep running to remove the heat from inside the car through the air con system. The noise on our C3 seems louder than on our other cars but could be due to being a small car and sat nearer the compressor or less soundproofing.

 

Thanks,the noise does come from that area. Not sure what you mean by should be happening frequently when the air con is on, do you mean should clunk frequently? my dad also has c3 (08 plate) and this doesnt make this noise. Is it only on older versions? Mine is 1.4 desire 05 plate.

[paul.h]

The clunking noise will happen frequently when the air con is on and when not moving you will notice the noise more. Running the compressor on and off is a way of controlling the air con system by controlling the pressure of the gas being circulated. At low cabin fan speeds it may clunk more frequently than at higher speeds since less cooling of the cabin is wanted yet the compressor will have been designed for the maximum case so at low demand it will switch on and off. Our C3 is a 2003 1.4sx petrol with manual air con - may be with an auto system (climate control) there will be more control by admitting warm air rather than switching the compressor. You could try an internet search to see how a car air con system works.

[Guest benny147]

The clunking noise will happen frequently when the air con is on and when not moving you will notice the noise more. Running the compressor on and off is a way of controlling the air con system by controlling the pressure of the gas being circulated. At low cabin fan speeds it may clunk more frequently than at higher speeds since less cooling of the cabin is wanted yet the compressor will have been designed for the maximum case so at low demand it will switch on and off. Our C3 is a 2003 1.4sx petrol with manual air con - may be with an auto system (climate control) there will be more control by admitting warm air rather than switching the compressor. You could try an internet search to see how a car air con system works.

 

Thanks Paul, that makes sense and fits with the frequency I hear the noise. Cheers for your help