"revving" noise from aircon

Colin Crossley · 29th May 2007, 07:45

Recently I have noticed that when the a/c is on (auto), there is an increased sound when accelerating or decelerating in low gears. The noise "follows" the revs of the engine. As soon as the a/c is switched off (econ) it stops. I've checked the fan and it seems to be OK, and the a/c seems to be chilling the car and clearing the screen OK.

Anybody any thoughts on this please.

myjess · 29th May 2007, 14:10

I posted the exact same here or the other forum a whie back. I thought it was the A/C clutch or the bearing or sime such. Others think it is a fan. I am still going with clutch cos you can hear it clicking in and out. What you could try is to gently pulse rev the engine. Wait for the A/C to be coling properly. Switch off the A/C and listen for the noise to disappear, then switch the A/C back on again. The A/C may not engage exactly at that moment becuase it is still cool enough, but when it does and the A/C compressors clutch drops, then maybe the noise wil immediatley come back, and then proof that it is the compressor's clutch?

29th May 2007, 07:45	#1
Colin Crossley Newbie MG ZT Join Date: Nov 2006 Location: Frodsham Posts: 27 Thanks: 0 Thanked 0 Times in 0 Posts	"revving" noise from aircon Recently I have noticed that when the a/c is on (auto), there is an increased sound when accelerating or decelerating in low gears. The noise "follows" the revs of the engine. As soon as the a/c is switched off (econ) it stops. I've checked the fan and it seems to be OK, and the a/c seems to be chilling the car and clearing the screen OK. Anybody any thoughts on this please.

29th May 2007, 14:10	#2
myjess Avid contributor Rover 75 CDT Join Date: Dec 2006 Location: Stokesville Posts: 115 Thanks: 0 Thanked 0 Times in 0 Posts	I posted the exact same here or the other forum a whie back. I thought it was the A/C clutch or the bearing or sime such. Others think it is a fan. I am still going with clutch cos you can hear it clicking in and out. What you could try is to gently pulse rev the engine. Wait for the A/C to be coling properly. Switch off the A/C and listen for the noise to disappear, then switch the A/C back on again. The A/C may not engage exactly at that moment becuase it is still cool enough, but when it does and the A/C compressors clutch drops, then maybe the noise wil immediatley come back, and then proof that it is the compressor's clutch?