AC Noise

The air conditioning on my 2007 Audi S3 makes a peculiar whining noise. It sounds like it's coming through the stereo (but it's not!) it's so
pronounced, and varies pitch by engine speed. It stops the second the AC Off button is pressed. Otherwise the AC works very well.
I've asked a few times on the Audi forums, and a local garage, but not found an answer. Somebody suggested I spray WD40 hopefully around the compressor to isolate the cause, but I'm not sure about that.
Any ideas?
--
Cheers, Rob

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 27/06/2018 17:46, RJH wrote:

Could be a bearing in the compressor, possibly due to low coolant.
Talking to others, it seems some cars are prone to gradual coolant loss in A/C systems. How gradual seems to vary. We had an Espace which didn't seem to lose any in 13 years. Our Honda CRV needed topping up after about 10 years. I've heard of far shorter periods. I know someone with a VW which was low after a couple of years and needs topping up again after another couple but VW insist there isn't a leak.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Brian Reay wrote:

I had an Avensis that never needed topping up in the 7 years I owned it. Other cars: Vauxhall Corsa and Vectra, Skoda Octavia - none ever went more than 2 years without needing re-gassing. The Corsa only lasted about 6 months and the main dealer tried to re-gas it several times under warranty in its first summer - after which it needed re-gassing every summer for the next 12 years.
--
Graham J



Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 27-Jun-18 6:46 PM, Graham J wrote:

The pressure valves are a source of undetectable leaks, it's where the pressure gauge fits with an o-ring fitting. The caps should have o-rings, if they don't find some that do.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 27/06/2018 18:46, Graham J wrote:

my focus is 18 and the air con is pefect and has definitely never been regassed or topped up. The air con is never intentionally turned off.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

My 04 reg Focus is (obviously) 14. The AC does work, but as the local tyre place re-gasses and blows debris that has accumulated for £60, is it worth a punt?
--
Ian

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 27/06/2018 22:24, Ian Jackson wrote:

Not if it's Kwik Fit.
--
Robin
reply-to address is (intended to be) valid
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 27/06/2018 22:38, Robin wrote:

with a modern ac regas unit , it would be hard to cock it up.
I am surprised that a/c places are still so cheap, a cylinder of r134 has gone from 60 quid to 400 in the last two years.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

I've had my 04 Focus since 2007 - and recently had my first puncture with it. ATS fitted a new one for £45 all in, and I asked the guy about their £60 re-gas offer - and he said it was a very good price as the price of gas had recently gone through the roof.
--
Ian

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 27/06/2018 22:44, MrCheerful wrote:

2012 Fiesta. A/C working but not as cold as it had been. Taken to KF. They reported the a/c was not working and needed repair. When driven away compressor no longer cut in.
I took it to a/c specialists I and family have used for years, and sat drinking their coffee and watching while they found (a) the system was totally empty, (b) it held a vacuum and (c) it worked fine when regassed. It is still working fine 9 months later. They told me it was not the first time Kwik Fit had managed to cock up what should have been a simple regas.
If it was a cock-up: Kwik Fit had of course gained the gas they extracted, so with what you say about the price of it...
--
Robin
reply-to address is (intended to be) valid
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 27/06/2018 22:44, MrCheerful wrote:

But how many of the big chains also offer the "free" safety check with every regas where they then find another £100 of work that the customer has to have done?
My 17 year old Focus, which I have recently disposed of, had one regas in its life and the AC was working for all of that time, except it wasn't getting as cold as previously before the regas.
--
mailto : news admac myzen co uk

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

No - ATS.
--
Ian

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 27/06/2018 22:24, Ian Jackson wrote:

GroupON has (or had) a special offer at ATS to have it done for half price at ATS the other week. I used a similar deal a year or so back, not trouble.
You get a voucher online, contact your local ATS place and book in.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 27/06/2018 17:46, RJH wrote:

Have you eliminated the possibility that the belt could be slipping under load? May be worth checking the tension.
--
Cheers,
Roger
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 28/06/2018 12:49, Roger Mills wrote:

spraying water on the belt while it is making the noise will show if the sound changes (without any risks)
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 28/06/2018 14:07, MrCheerful wrote:

*Not* without risk! Tensioner pulley bearings are quite likely to fail if you spray water on them. I know from bitter experience!
--
Cheers,
Roger
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 28/06/2018 22:24, Roger Mills wrote:

If you pressure wash them, maybe. But every rainy drive will get water around the engine bay, so they cannot be that precious.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 28/06/2018 22:46, MrCheerful wrote:

I had mine fail *twice* on the same car within a few miles after washing the engine with a hose (*not* a pressure washer). It was only after the second occurrence that I put two and two together!
--
Cheers,
Roger
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 29/06/2018 16:29, Roger Mills wrote:

Bloody hell, I hardly ever wash the *outside* of my car, let alone the engine!
But more seriously, I'd have thought you could do Mr C's test with a water pistol or garden sprayer without killing the pulley bearings.
--
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 27/06/2018 17:46, RJH wrote:

Thanks for all the comments. Just back from a £75 Audi AC service - inspection, empty and refill according to the advert. The noise has now gone.
Didn't stop them spending 4 hours poring over the car trying to find the noise after they'd regassed it. They did manage to find £400 worth of 'faults', though ;-)
(And £2.5k for a clutch/flywheel - it's started slipping during mad acceleration - but not noticeable normally. So I'll leave that one for a bit)
--
Cheers, Rob

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here. All logos and trade names are the property of their respective owners.