How can i check if my air con just needs gas?

[Mungo2007]

Hi all 

I need some advice on the air con on a 2008 A3. 

When the car is started i get a bit of cold air for about ten minutes and then it goes warm, is this just a case of needing re-gassing or are there other things i need to check?

I did read on another post about the red lights on the dash mine has the air con light on and the Econ light on is this correct? Not sure if it makes any difference. 

Thanks 

Duncan 

[Steve Q]

Hi Duncan, yes it may just need a regas but get it checked for leaks if you are having it done. 

It can also be a pressure sensor. 

Cheers

Steve

[Mungo2007]

Is there any way to test the pressure sensor? 

I am hoping to re-gas myself there are some decent looking kits online that have good reviews, buy the kit to start which is gas, leak stopper and the regulator for about £55 but then when you need to gas another car the cost is around £17 for the gas as i then already have the regulator. i just wanted to give the system a check first to make sure i am not wasting money for the gas to come out the other side or something more sinister like a compressor problem, i am sure the system just needs gas as i get cold air for a bit.

[cliffcoggin]

I believe the Econ mode disables the aircon. Try turning Econ off.

[Steve Q]

15 hours ago, Mungo2007 said:

Is there any way to test the pressure sensor? 

I am hoping to re-gas myself there are some decent looking kits online that have good reviews, buy the kit to start which is gas, leak stopper and the regulator for about £55 but then when you need to gas another car the cost is around £17 for the gas as i then already have the regulator. i just wanted to give the system a check first to make sure i am not wasting money for the gas to come out the other side or something more sinister like a compressor problem, i am sure the system just needs gas as i get cold air for a bit.

If you're going to the trouble of buying the kit then you may as well buy the dye that you can put in the system to test for leaks 👍

[Mungo2007]

Yes may as well. 

Will feed back on the home re gas kit once i have tried it 

[Steve Q]

4 hours ago, Mungo2007 said:

Yes may as well. 

Will feed back on the home re gas kit once i have tried it 

Please do as I'm curious as to how these kits work etc 🙂

Cheers

Steve

[John Reid]

I made my living repairing and servicing car air conditioning for about 8years....but have now retired. Firstly the visual check....find the gas condenser which is mounted ahead of the cooling radiator...looks a bit similar....check for any oily looking patches....these will be where the aircon gas has escaped and taken some of the compressor lubricant out with it. If it looks dry and serviceable find the pressure switch,which is likely to be on the ali pipework going across the bulkhead...might involve lifting the plenum chamber plastic cover.Check again that it's dry.

Check the compressor next...if the two terminals are easy to get to apply 12volts and observe the clutch plate on the end of the compressor coming together to give it drive,either polarity.If the clutch draws in with a click try it with the engine running.

Now to add the gas to increase the efficiency......engine and system cold....feed gas through the low side port...the smaller one...until the a/c system has equal pressure with the can.When gas stops flowing turn the can off. Start the engine.....call for full fan and full cold....the econ button turns the system OFF. Watch the pressures increase and monitor the inside temperature.Soon observe the additional cooling fan come on either half or full speed. When the systems settled...2-3 minutes allow more gas to be drawn in through the low side until you have good cooling......do not over gas because over pressure is sure to find any leakages.

[Mungo2007]

thanks John i will got through you advice 

[Mungo2007]

I said in an earlier post i would feedback on the kit i bought. Ordered Thursday and arrived Saturday they do have a website but i got the kit on eBay. 

I thought i would start with the Q7 i have that needed gas, kit comes with great instructions but i did have an issue and was not sure on something so rather than cause myself problem i waited until today and spoke to the company about it. GREAT support from them talked me through the whole process while i was with the car. 

I had to put in a leak stopper can first to seal the system only because the gas was so low you don't always need this (only seals the O rings) then i put the gas can on the system and it is perfect runs nice and cold and done in about 15-20 minutes. 

I don't normally leave reviews but this product and company are worth it, great product and really good support which is something you don't get nowadays. 

Not sure if i am allowed to put web links on so please remove if not the web address is http://www.aircontopup.com/

There are plenty of videos online for the products as well so you can see how it works. 

 

 

[John Reid]

Hi Duncan......I wish you well with the leak stopper....you must run the a/c as much as possible to ensure that it travels around the whole system....I 've known may driers block solid....if system drops again look for possible freeze ups.....ice on outside of components....good luck. John.