Volvo S60 - strange intermittent air-conditioning noise - WITH POTATO VISION

[rantingYoof]

Car - 2005 S60 2.0T manual.

 

Car is misting up a lot at the moment, indicating possibly duff pollen filter or something, but either way I'm running the air-con a lot pointed at the windscreen, which clears it nice and quick.

 

Anyway, just dropped family back at home after Christmas celebrations and, when parked up, noticed that every 20ish seconds, there would be a rather loud "WHIRRRRRR" or "BRRRRRRRR" noise from under the bonnet, which would last for maybe 5 or 6 seconds.

 

Perhaps the best description of this noise is a small motor that is trying to move something that has got stuck.

 

Fortunately, I grabbed a video and a photograph of where the noise was coming from - this box with the orange/copper wires in it (photo has been rotated 90 degrees anti-clockwise by the forum's uploader)

 

 

Video [filmed on a Potato S2 in SUPERINYOURFACEZOOMMODE]

 

I realised that the car was sitting there on idle with the air-conditioning running and the fans on around the third or fourth power-setting, keeping the windows clear.

 

The air-condioning works splendidly - it blows ice-cold. The car runs absolutely fine. There are no apparant leaks or other issues.

 

Is this a normal air-conditioning-is-working-and-the-Volvo-is-just-quirky noise, or is this a your-air-conditioning-is-about-to-shart-itself noise?

 

I can live without air-conditioning myself. However, if this thing goes phut, is it the sort of thing that can FUBAR other critical components?

 

Any advice, even if it's just mocking for my general ignorance, is duly appreciated.

[HH-R]

It's not the electric radiator fan, is it? They can make a fair old racket.

[HH-R]

Helps if I read all the thread... thing with orange wires in it looks like the alternator. Bad bearings maybe?

[rantingYoof]

I imagine the alternator would "kick in" when the car is using more electricity (i.e. if the air-conditioning was on), so this is certainly possible.

 

When I turned the air-conditioning off the sound stopped. I needed to turn it back on again as the car was misting up quite a lot, and I heard this noise inside the car as I slowed down and stopped at some traffic lights.

 

I know a broken alternator = bad news. Excuse my ignorance - what part do bearings play in the alternator?

[HH-R]

If that is the alternator (and I will look pretty red faced if it isn't! ), it runs all the time the engine is running*. The more electrical items you have on (lights, heated rear window), the harder the alternator is harder to turn because more is being asked of it. Sometimes in winter the belt can slip and squeal when pulling away if it's already not tip top and there's headlights/interior fan/radio etc on. The alternator is just a shaft with a magnet on the end that turns inside the orange coils so there will be bearings around the shaft, they can sound a bit gratey if they're on their way out. I don't have any speakers plugged in so I haven't heard the noise but if it's coming and going it could be the air con compressor itself that's noisy when it's running. Might be the radiator fan tho? They usually run when air con is on, especially if the car isn't moving.

 

*There's some smart charge thing on some cars nowadays which might make it cut in and out but that's waaaaaaay too modern for me to know anything about.

[hauserplenty]

Try turning the lights on hi-beam, then the heated rear window (if equipped) to see if you still hear the noise with the AC off. If not, turn the AC on and the blower on low, and see if the noise is still present with the blower on low or on high. If the noise occurs only with the AC on, it points away from the alternator and towards the AC compressor clutch instead. To rule out the compressor, you can try unplugging the wire harness leading to it, and turn the blower motor up to high and listen again.

If it was the alternator, there would likely* be a more constant noise, and the lights might also dim. A voltmeter placed across the battery terminals should read at least 13V, engine on. Sounds to me like a cooling fan as mentioned, or the AC clutch.

[Split_Pin]

Def agree on the compressor causing the noise. Its belt driven so unlikely to out more load on the alternator.

[carlo]

One of my Rover 75s made a right racket (sort of whining/groaning) with the air con on; switch it to 'ECO' i.e. turn off the a/c and the noise went.  Was told it was just a noisy compressor.

 

Once you know what it is you can live with it if it ain't too serious.

[rantingYoof]

All sounds relatively reassuring. I've gotta do 250 miles tomorrow and want peace of mind that the car will do this without worrying about it and if anything relating to the air-conditioning decides to FUBAR the car won't go "NOPE" and stop on the A34.

[NorthernMonkey]

These have a 'free-wheeling' pulley on the alternator which quite often seizes, the symptoms of which sound very much as described. Not massively expensive to get a new pulley fitted...about ten minutes work if you have the right tool.

Don't want to cause you undue worry but be careful...if left too long, the aux belt can jump off and shred itself, which quite often then goes through the cam belt cover, taking that belt with it and effectively destroying the engine. I have seen the resulting mess on several occasions and it ain't pretty!

[NorthernMonkey]

Having said all that, the ones I've known this happen to have been the D5 engined models and I've just noticed yours is the petrol model...as mentioned elsewhere, it could well be the air-con clutch that's noisy also, which doesn't necessarily have the same dire consequences.

If the noise disappears when the AC is off, then that's the most likely cause, so please......don't have nightmares!