Aircon actual temperature

[MoRS6+]

This old chestnut again.

I know the weather has been really crazily hot this week and it has tested my aircon to the max trying to operate in a mobile kiln! I don't quite know if it is performing as it should or whether it is just being overwhelmed by the mad heat - I swear it should be colder. What should the actual temperature at the vents be (on LO obviously) and what is the best/cheapest way to measure it (just seen a cheapo digital thermometer on Maplins website for 19.99 - could I use that?)

If the temp. is too high, does it mean I need a re-gas?

Car is a 2004 'plus' with 20k on the clock.

Cheers,

Mo.

[onlinesys]

Over here in Asia, the temp. in the day time is 33 degree C and 30 degree C at night. I've just picked up the car from the garage this late afternoon and the cabin is cool within 3-5 minutes (I set it to AUTO) and when I got home after 20 minutes drive, the aircon fans are actually at the slowest (I set the right/left temp. at 20 degree C). Can't give you any actual data but just my experience which might give you a bit of insight.

[MoRS6+]

I remember watching an episode of 'Wheeler-Dealers' recently and they had the aircon on a Corvette re-charged and the bloke had a digital meter which read 4 degrees at the vents when he'd finished re-charging. Should it be the same for the Audi?

[Rupert]

One of my cars reads 2.0 degrees at the vents. Occasionally I can SEE the air coming out (white mist), it's like when you open a freezer door. It's 10 years old and has never had any air-con regassing. I haven't measured the RS6 aircon but I know it is not as cold.

Try setting the aircon on recirulate or auto-recirculate as it won't need to draw in 30 degree air from the outside then.

[Shoppinit]

Mo, I'm in the same position as you. Just suddenly got the feeling that my aircon should be blowing cooler than it is. I'm just going to go and get it recharged by an independant. It's a pretty cheap operation. At least, it was on my other cars... I wonder if I'm in for another Audi-flavoured nasty surprise!

[BigMo]

Suggest you go to engineering and let them look into the environental conduits

[mac2]

im told it should be between 3 and 5 degrees and you should have it recharge every year. its changes the oil as well to help look after the pump etc.

[el_ringo]

A cheap fridge thermometer would do I guess to check the air temp. Do you have it set to ECON a lot in the winter? It could have leaked gas or the pump has ceased. Halfrauds do a recharge bottle with a pressure gauge, not used it on my '6 but fixed a nurses 206 and confirmed my old Mondeo was full of gas.

[mac2]

the garage i use in maidenhead have a machine have a aircon machine that reoils;checks for leaks, and regasess for 45 quid and they are a good bunch of guys

[mattler]

On "lo" the vent reading should be between 3 and 5 degrees in this heat

[kbee]

been viewing your post,just to clarify temperatures inside are all totally dependant of ambient temp but 5 degrees is about the best you'l get you prob just need routine re-gass but the oil can only be changed by removing pump & all other components ie condenser /evaporator/reciever dryer,you only replace the oil that comes out during extraction & vacum periods of the service hth keith.

[MoRS6+]

Think it was just that Wed and Thurs were extremely hot days because yesterday was slightly cooler and the aircon didn't seem overwhelmed. In fact, I had to turn it off as the cold air made my eyes water. Think my expectations were slightly high, especially as the car was like a hot oven on those 2 days as it was out in the sun.

[Cornishmoocher]

The hoter the ambient, the less effiecient your AC will be. Period.

between 3-5 deg.c? way too low, that would put the evaporating temp below freezing and would lead to a frozen coil and a loss of efficiency. I would expect to see an air of of betwween 9 and 15 degrees c, which gives you the magical TD of 6 degrees c.

If you are supplying air at 3-5 degrees c, sumut aint right!! Please trust me.
Mine is working perfectly and was supplying air on Tuesday with a ambient temp of 34 deg C at a perfect 16 degc.

You also have to remember that all temperatures are relevant. Supplying temps at 3 deg with an ambient of 30 would be after a short period of time uncomfortable, as if the cabin is air tight and you are running it on recirc as you should when on full, the laws of phsyics say that the cab temp must eventually reach.......3 deg c. Basically your car is a fridge...... I think not!

As mentioned above, oil changes- why? have you doen an acid test opn the oil? has become saturated (it is hydroscopic)- this is the only feasable reason for carryibng out an oil change. It is a really long protracted job, as you need to remove ALL the oil, so involve flushing the system, and woulkd take the best part of a day easily.
Guy's i am not beuing a C*nt here, but trying to stop you from spending money (even 45 quid) and warn you about being drawn in by unscrupulous p[eople who will tell you anuthing aboout AC to lighten your pockets.
AC is a pretty exact science, and while regassing is straight forward it worries me, that some of these so called experts seem to know nothing about the science and chemistry involved, and the effects of 1 gramme of extra or less gas will make, and if they need to "replace oil that has been removed from vacuuming"- I would be reporting them to ACRIB, CITB and the trading standards, because they should not be trading. Its a physical imposibility.

I am more than happy to answer any questions you may have, I know how important this stuff is to us, and cant bear the thought of any of us being A) ripped off and B) putting our pride and joys at risk.

Mooch.

[MoRS6+]

Cheers Alex. Just wanna pick yer a/c brains fer a bit - how comes on that episode of wheeler-dealers that a/c chap stated 4-5deg at the vents? And, what would be the best way to measure the temps at the vents on my car?

Cheers,

Mo.

[Cornishmoocher]

Because he is wrong.

Just get a cheap digital thermometer and take the temp from each of the vents, add it together and then divide by the number of vents, that will give you your average air off temp. Anything lower than 8 degrees c for my liking is too low.

You have to bear in mind that the system works on a return air/fresh air make up principle.

Lets say yuo have your AC set to 20 degreesC. Lets suppose the ambient is 15 deg C, the climate control will use a percentage of the cooler air to lower the cabin temp, and only if after a certain period of time OR interior temperature increase will it engage mechanical cooling. Once the return air reaches 19.deg C the mechanical cooling will cut out and then the fresh air make will regulate the temperature until the mech deadband is exceeded where the compressor will again cut in.
However, if the ambient is 30 degrees, and the interior is 40 degrees as it sometimes is when you get into the car, the AC will mech cooling will cut in straight away. BUT and ITS a big but, the heat load that the AC has to cope with in that situation will mean that the cooling will not be as "cold" as it could be untill the cabin temp drops and the heat load is reduced. In that situatio, as you wouldn expect, the AC should stay on permenently and just slow the fan down as the return air temps reduce.