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How can you tell when your AC needs re charging/re gassing?

Discussion in 'A3/S3/Sportback (8P Chassis)' started by AidenUK, Nov 7, 2011.

  1. AidenUK
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    AidenUK Well-Known Member

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    [Nov 7, 2011]
    Seems to be steaming up a bit lately, ALWAYS have the climate on in the A3 and never noticed this before.

    My question is, how do you know when the AC needs a re gas? Does it show up on VCDS with an error code? Don't wanna be waxed for 50 big ones if it's just down to the cold weather setting in, if it needs doing then i'll do it but i'd rather know 100% before i throw money at it.

    Thanks
    #1
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  3. rickypj
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    rickypj Member

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    [Nov 7, 2011]
    You know you need a regas when the AC doesn't work... switch it on and check if you get cold air when on min setting and see if the cooling/condenser fans come on under the bonnet. If not then you might have a leak and be low on refrigerant which will cause it to not run the compressor due to low refrigerant pressure. If the condensor /cooling fans do come on them you have enough refrigerant/gas in the system and the problem is probably something else.
    #2
  4. TimG
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    TimG Active Member

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    [Nov 7, 2011]
    I would say when it no longer pumps out cold air, but I never use mine winter or summer and my car never seems to steam up whatever Im doing. Maybe I need to get Kate Winslet in there :)
    #3
  5. AidenUK
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    AidenUK Well-Known Member

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    [Nov 7, 2011]
    It might just be me mate, it does feel cold but not as cold as it used to be but then again that might be because it's not hot outside!
    #4
  6. alfiejts
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    alfiejts Member

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    [Nov 12, 2011]
    I had a really good conversation with an aircon specialist, so just thought that I'd share to answer this query.....

    I had the aircon on my A3 serviced as it was seven years old and although it was still working, it wasn't cooling at well as it used to.

    Firstly - if you want to test the performance of your aircon, hold a thermometer in front of the outlet vent with the aircon on full chill (set to "LO"). If you have got one of those "meat probe" temperature sensors, you can stick it into the centre vent to take the temperature of the air as it comes out of the vent.

    His basic "standard" is that if the output temperature is 8 degrees or lower, then the system is working to an acceptable standard. If its chilling but doesn't go as cold as 8 degrees (mine was 10) then it definately needs a regas...

    After being serviced, the air out of the airvent was down to 5 degrees - much colder.

    Out of interest, I took our kitchen meat probe and stuck it into the centre vent of our three year old Yaris - and the temperature went as low as 3 degrees. Yippee - that's still working just fine - and even colder than the just serviced Audi....
    So there's your benchmark if you want to test your aircon. Working perfectly, it should be able to chill the the temperature of the air coming out of the air vents down to at least 5 degrees max...)

    Secondly (I did know this but share it for anyone who isn't aware) - you should run the air con for at least ten minutes every week or so. When you run it, the oil inside the system circulates and lubricates the rubber pipes and seals. If you don't run it regularly, they dry out and that can lead to premature failure and leaks.

    Finally, (and this is the nugget of info that really was new to me) even if the system is still working perfectly, you should change the refrigerant every 3-4 years. (Garages will try to get you to do this every 2 years, he says, but only every 3-4 years is really necessary according to my man...)

    The reason you need to do this is preventative. Moisture gets into the system over time - but it doesn't just make the system less efficient, the moisture combines with the refrigerant and it turns it acidic, so that it actually starts to corrode the pipes and seals from the inside.
    So you really do need to get a proper service every few years to remove all the contaminated refrigerant and replace it with fresh, to stop the internal corrosion damaging the system.

    So that's why, even if the pressure is low, its not worth buying one of the top up DIY cannisters - you need a proper professional vacuum system to extract all the contaminated fluid and replace it with fresh. If you just top up the pressure with a diy can, you've still got the original moisture-ridden refrigerant in your system.
    Better to spent £50 on a proper job than £30 on a DIY can....
    #5
  7. mike foster
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    mike foster Fossie VCDS Map User

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    [Nov 12, 2011]
    Wasn't aware of a lot of that - many thanks for the info mate
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  8. mikex709
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    mikex709 Member

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    [Nov 12, 2011]
    Ditto, thanks for the info :)
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  9. Baffles
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    Baffles Member

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    [Nov 13, 2011]
    Had mine done yesterday - smells so fresh now as previously it did get a bit stale on the colder temperatures.
    #8
  10. box500
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    box500 Member

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    [Nov 13, 2011]
    You can also do a quick check and ensure your cabin filter is new/fresh as they can cause condensation (so I have heard) when the get clogged up.
    #9
  11. AidenUK
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    AidenUK Well-Known Member

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    [Nov 14, 2011]
    Thanks for all the replies. I'll just get it re gassed, it probably hasn't been done since it was new!

    :icon_thumright:
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