Aircon minimum outlet temperature

[Old Webbo]

Just had my annual service which included an aircon service, problem now is that I'm not convinced the air is being chilled any more and is just blowing in air at outside temperature. It was around 12 degrees C yesterday so with the Climatronic on 'LO' setting I would have expected to notice a difference. Took it out again today but with outside temperature around 8 degrees C it wasn't possible to discern any cooling. I intend to do some actual temperature measurements to see what the differential is, if any. Does anyone know what is the typical minimum temperature the aircon should be able to achieve. It would be a lot easier on a warm summer day to determine if the aircon was functioning but I can't wait that long if a need to take it back to the garage for a free fix.

 

Thanks all

[FlexibleMouse]

I think 16 or 17 is normally the minimum

[Ootohere]

hutchysrs50 or some other member had in a post recently in a thread with the sequence for pushing and holding AC Buttons which i tried and then the 

cooling was left set getting Lo  even Lower.

 

No idea what i did,

& i was warned it could mess everything up, but luckily not knowing what i was doing gave a good result.

[SuperbTWM]

Why would you think an air con service would make it work better? If it was working fine before you aren't going to notice any difference.

 

As you have already figured out you can't test the AC very well without some warm weather, if it was working at full load the evaporator would freeze up so its probably holding back with an ambient of 12C. 

[Old Webbo]

I had the service done because the air con had not been re-gassed for about four years and was not as cool as it used to be during the last summer. There was also an offer to have air con service and brake fluid replacement done at a reduced price. Not so sure now that it was a good idea. I'm fairly convinced things aren't quite as they should be but want to be sure of my ground before taking it back to the garage. Just need a good way of testing it in cool weather.

[Breezy_Pete]

I can do VCDS log in the morning if you like. It'll be a climatic system on a 9n Polo, but the physical/physics bits will all be the same, I would think.

[octyal]

It used to be that the temperature was measured at the vents, and it wasn't supposed to be lower than 4 deg C I think. Bare in mind that with the climatronic on ECON, that you aren't using the air con, just the fresh air blower, you need to put it into AUTO and adjust the temperature down to get the cooled air.

[Breezy_Pete]

Log done, will post a graph later.
2 Celsius at whatever vent you choose is the quick summary.

 

Click image to enlarge:

 

Edited 15 December, 2016 by Wino

[Old Webbo]

Thanks Wino, very useful. Checked mine again today, outside temperature around 10 degrees C. Putting the system on maximum chilling (temperature dial to 'LO') there is no discernible temperature difference with AC on or not. I don't know if the Climatronic system behaves differently to the Climatic. As I don't have a temperature calibrated hand I bought a temperature probe device at Maplin today which should give a better indication of what is going on. Looks like a return to the garage is called for unfortunately.

[Breezy_Pete]

No problem. I forgot to mention, that was with temperature dial set to lowest setting.

[Old Webbo]

Took some measurements today, outside temperature was about 8 degrees (as indicated on MFD thermometer), no sunlight (it was dark). With Climatronic set on 'LO' the vent temperature measured about 10 degrees ie no cooling effect whatsoever. It was still cooling the cabin effectively so I'm not sure if it is meant to behave this way to save power, when the outside temperature is sufficiently cool. Really need a warm sunny day but might have to wait a while for one of those. For those of you with the Climatronic system would really appreciate if one of you could conduct a similar test to see if additional cooling is applied when the outside air is already fairly cool but above the low temperature cut off point for the air con to work at all.

I am booked in at the garage later this week but don't want to look a complete idiot, well no more than I have to.

[Old Webbo]

Still struggling with this - have now had sufficiently warm days just recently to prove the air con does absolutely nothing, the compressor does not seem to be active. Does anyone know if the Climatronic panel has a test mode and also the location of the low pressure switch (assuming there is one). There does seem to a switch of sorts on the high pressure side (on the narrower of the two pipes).

[Breezy_Pete]

I'd be looking at the compressor pulley to check that everything you can see is rotating (there's a fail-safe mode that shears off a rubber coupling, causing the outside of the pulley to still spin with the aux belt, but the centre/shaft to not rotate).

 

If that's all spinning together I'd be looking at the connection en-route to the compressor solenoid valve. On a mk1 this is on a bracket hanging off the front of the gearbox, a two-way connector pair in a rusty brown colour plastic.  Also check the two wires going on from there to the connector on the compressor, make sure there are no broken wires near any of these connectors.  As I don't know if the connectors are the same colour on a mk2, maybe best to follow the wiring back from the compressor to make sure you're looking at the right ones. I think this may only be possible from beneath, possibly with any obscuring engine undercover removed.

 

If that checks out, you could have a look at the connections of the refrigerant pressure sensor (known as G65, it's a sensor not a switch, I don't think there are any of those). Pretty sure this will be the one you've found. Make sure none or the 3 pins are corroded or wet.

 

If you have or can get access to VCDS, one of the measuring blocks of the AC control module will give a so-called 'compressor shut off code'.  This is 0 when AC is switched on and working without fault, but some other number according to the nature of the fault/reason if the compressor has been shut off due to a fault condition.

Codes are defined here (plus a great set of diagnostic tips).

 

 

 

Edited 27 February, 2017 by Wino

[Old Webbo]

Thanks Wino. I don't have access to VCDS so unfortunately I'm in the hands of the garage, its booked in next week. I suspect they under filled when the air con service was done, I just hope the compressor hasn't been damaged in the process of running low (although it hasn't engaged as such with no attempt at cooling). Will post an update.

[Old Webbo]

Just an update on this, back to the dealers today. Refrigerant was low so after a check for leaks it was re-gassed and now OK (blowing at 4-5 degrees C). Suspect it was insufficiently charged when last re-gassed as it stopped working more or less straight after this. Dealer said gas was only a little low but for the compressor to stop working entirely I think it was significantly low. Hope it hasn't been damaged in the process as that will be another battle on my hands.