Picasso aircon noises

[mnde]

My current car is the first I've owned that has AC... so I'm not very knowledgeable about it!

It recently started making whirring whooshing noises that come and go regularly, usually under engine load rather than idling. If I switch the AC off, the noises go away. My garage thought it was because it was working hard in the heat but it didn't do it last summer! It still goes nice and cold, but I'm wondering (hoping) it's overdue an AC service and not anything more costly... The auxiliary belt was changed last year. What do people think?

Cheers!

Mark
Xsara Picasso 1.6 16V petrol

[GiveMeABreak]

That's the first thing to do - get it serviced and regassed at somewhere like Kwik Fit - a swooshing noise can mean the gas is getting low. It's not good to leave it low on gas. I don't know when it was last topped up or checked, so would be a good idea to have it done. They usually do a vacuum out of the gas and oil, clean and disinfect the system to kill all the bacteria, then replace the gas and oil in the correct quantities.

[mnde]

Thanks Marc, will do. I don't know when it was last checked/recharged either and I bought the car in Oct 2017 so it's due either way!

[Harlequin]

ATS have a voucher on groupon right now for a £37.99 aircon service

edit:

https://www.groupon.co.uk/deals/ats-euromaster-ltd-21

be quick it`ll be ending soon

[mnde]

Thankyou - I missed the Groupon, plus my ATS branch didn't have a slot today so I booked it with Merityre and had it recharged today. I mentioned I'd been hearing some noises.

The aircon was cold... now it's super freezing. But still some noises so I'm wondering if it's either the aux belt, the clutch or the compressor itself. It certainly sounds like a slipping noise, so if I engage AC with increased revs it does it. Don't know if its me but it feels there's more resistance with the AC on than normal. However my car is still recovering from the oil in the injector loom, so it could be some hesitation as well.

First question: if it's the clutch, can it be replaced separately to the compressor? Also is there a way I can diagnose whether it's the clutch or compressor?

I use my AC throughout the year, so it's never been inactive for very long. The aux belt was replaced last year.

Thanks!

Mark.

[GiveMeABreak]

If it's a slipping noise - then it's more likely to be the belt or the pulleys if you have had the belt changed. Of course you will get an increase in engine revs as the A/C puts more of a strain on the system, so the engine ECU compensates by increasing the engine revs when the A/C is on.

[mnde]

If it's a slipping noise - then it's more likely to be the belt or the pulleys if you have had the belt changed. Of course you will get an increase in engine revs as the A/C puts more of a strain on the system, so the engine ECU compensates by increasing the engine revs when the A/C is on.

Thanks It's hard to describe... Not slipping as in squealing, but like a pump whirring (and whooshing). I can make it happen by engaging AC in neutral with increased revs, but not if I rev the engine with the AC already on. But it does happen on hard acceleration in gear.

I've looked on service Citroen to get part numbers, and it appears it's possible to get a compressor clutch kit. Didn't realise it was magnetic action, so not sure now about clutch slipping versus pulley or compressor bearings.... Other possibility, come to think of it, is a lazy clutch coil - wonder if oil could have got into the clutch coil electrical connection.... as it got into all kinds of other places! (see my other post)

Thanks,

Mark

[admiral51]

Not an expert by any means but is the noise there without the A/C engaged on hard acceleration?
Looking at your last post about the noise not being there when A/C already engaged and revved in neutral is it possible that the A/C is not the cause of the noise, just that it is being associated with the noise because that is when you first heard it ?
The Aux Belt Tensioner would be my first point of call as you say you have had oil spray issues recently and a recent Aux belt change.

[mnde]

Not an expert by any means but is the noise there without the A/C engaged on hard acceleration?
Looking at your last post about the noise not being there when A/C already engaged and revved in neutral is it possible that the A/C is not the cause of the noise, just that it is being associated with the noise because that is when you first heard it ?
The Aux Belt Tensioner would be my first point of call as you say you have had oil spray issues recently and a recent Aux belt change.

Hi there,

There are no noises when the AC is turned off, on hard acceleration, startup etc. They only occur when AC is engaged. I haven't had oil spraying, it was leaking into the main injector harness via a failing oil pressure switch, so I meant it reached a lot of places such as in the ECU, connections for the lambda sensors, the MAP, the motorised throttle housing... I've read that the ECU provides feed and ground to the a/c clutch coil, and there's other places I've not yet checked - A/C low pressure sensor, condensor temp sensor.

It is suspicious that this has started happening only since my fuel system problems, as in oil has been slowly migrating round to various places over time... Now I'm wondering whether the A/C symptoms are connected to the same problem.

But you're right aux belt tensioner, or belt tension itself are another thing I can check out.

Thanks,

Mark

EDIT: I forgot to say the relay still makes a nice loud click

[admiral51]

Hi Mark
Sorry should not have used spraying to describe your oil leak issue
If you have isolated the noise to only happening when A/C is engaged then it sounds like a mechanical noise, maybe get a stethoscope on the A/C compressor, could be the bearings are on the pulley ?
Just trying to help but guess just muddying the waters

[mnde]

Hi Mark
Sorry should not have used spraying to describe your oil leak issue
If you have isolated the noise to only happening when A/C is engaged then it sounds like a mechanical noise, maybe get a stethoscope on the A/C compressor, could be the bearings are on the pulley ?
Just trying to help but guess just muddying the waters

No worries at all, thankyou for your suggestions! Stethoscope hmm, I'll have a look on eBay see if there's one that's long enough to reach, and safely too... Ideally while someone else is in the car to turn the AC off, wait, then on again while holding say 1500 RPM in neutral.

Thanks,

Mark

[admiral51]

Have a look at Mechanics Stethoscope

Cheap and cheerful lol

[mnde]

Thanks, looks like it would be useful!

I've located the compressor and AC pressure switch wiring plugs in the Haynes manual.... Just need to see if I can get at them easily or not to check for oil contamination as a potential cause....

Mark

[mnde]

Sorry, another question: I can only find reference on Service Citroen and autodoc.co.uk to one pressure switch, mounted on the condensor. I'm assuming this is a low pressure sensor which cuts out the compressor if gas pressure is too low, and there's no separate high pressure switch function?

Thanks.

[GiveMeABreak]

Pop your VIN up and I'll take a look.