Car air con noises
Discussion
Yeah that's pretty normal. It's the AC clutch kicking in and out, especially when it's hot out. The compressor cycles on and off to keep the pressure right.
But if it's loud, like a grinding or rattling kind of noise, that's not normal. That could be a failing compressor bearing or low refrigerant.
If it's just a deeper hum or whir that comes and goes, don't worry about it. If it's getting worse, get it checked.
But if it's loud, like a grinding or rattling kind of noise, that's not normal. That could be a failing compressor bearing or low refrigerant.
If it's just a deeper hum or whir that comes and goes, don't worry about it. If it's getting worse, get it checked.
If it is more of a whistling noise the car night be a little low on gas.
This past few weeks has shown the issue as it is working really hard.
Under normal conditions you have enough gas but not enough forcthe curreng conditions.
There may be no leak your car might have just always been borderline on how much gas it had and the recent hot weather is showing this up.
This past few weeks has shown the issue as it is working really hard.
Under normal conditions you have enough gas but not enough forcthe curreng conditions.
There may be no leak your car might have just always been borderline on how much gas it had and the recent hot weather is showing this up.
What car is it? There can’t be many now with clutched compressors.
Wife’s Karoq was screechy in hot weather with a subtle (hard to detect until your ears tuned into it) kind of gentle hammering sound which seems to come behind the dash - as if there’s a little valve there that’s ratting / hammering.
I thought it just needed recharging but dealer changed the compressor under warranty.
The screeching noise hasn’t come back but the hammering is the same. While it was in they gave me an identical Karoq and that was noisy too! However we also have an Ateca in the family and that’s completely silent.
It annoys me enough that I sometimes dab the a/c off when stopped at traffic lights.
Wife’s Karoq was screechy in hot weather with a subtle (hard to detect until your ears tuned into it) kind of gentle hammering sound which seems to come behind the dash - as if there’s a little valve there that’s ratting / hammering.
I thought it just needed recharging but dealer changed the compressor under warranty.
The screeching noise hasn’t come back but the hammering is the same. While it was in they gave me an identical Karoq and that was noisy too! However we also have an Ateca in the family and that’s completely silent.
It annoys me enough that I sometimes dab the a/c off when stopped at traffic lights.
E-bmw said:
Sheepshanks said:
There can t be many now with clutched compressors.
Curious, surely all have clutched compressors, certainly all I have ever seen are.Makes sense if you’re trying to minimise the efficiency impact as much as possible; Adding the ability to modulate the output doesn’t negate the traditional clutch cycling strategy.
Haltamer said:
I m with you on this - I know both the Civic & Jag (2019, So quite recent) have variable compressors, but they both still have clutches too.
Makes sense if you re trying to minimise the efficiency impact as much as possible; Adding the ability to modulate the output doesn t negate the traditional clutch cycling strategy.
Perhaps it's a terminology thing - we had a Jazz and you get the clunk , whirr thing as the electromagnetic clutch cycles on and off and the main cooling fan runs at full speed with a variable duty cycle. The clutch had a stack of little friction plates.Makes sense if you re trying to minimise the efficiency impact as much as possible; Adding the ability to modulate the output doesn t negate the traditional clutch cycling strategy.
Our VW cars don't do that - the compressor has a variable swashplate in it to vary the output. My 2005 Merc was the same - in the Merc is ramps the a/c output down slowly if you turn it off and it's supposed to always run at 10% even when off.
There is still a mechanical "clutch" on the VW compressors, but it doesn't do anything - until it fails, and then the compressor doesn't work. I think it's there in case the compressor jams.
Maybe it's an emissions thing and some cars do have both variable compressors and electromagnetic clutches? But I haven't heard that "clunk" on a car for some time.
ETA: Bit of Googling says some cars - seems mainly "prestige" - use a magnetic drive now, with a variable rate compressor.
Edited by Sheepshanks on Monday 29th June 12:24
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