Air con problem??
 

Hi all,


Come to use the Air conditioner on full cool today and found it doesn't work. I put a temp probe into the middle vent and its 28 deg c when the outside temp is only 22 deg :confused: So its cooler to turn the blower off completely and open the windows.


I've put a VAS on the car and it only had one intermittent fault which was compressor pressure sensor intermittent fault. Ive cleared it and there are no more faults showing after hours of driving.


Refrigerant pressure is 4 bar.


how do you know if your running out of refrigerant??


Thanks
fRank

I know this video is not a Bentley, but it will show you the equipment necessary and the principles involved.

Thanks for that, I was hoping some one like Bentleytech would come on and explain if my VAS 5054a computer should tell me if the refrigerant level was low ?? All I could see was pressure sensor reading of 4 bar ??
Frank

hi,yes the vas should tell you if you have refrigerant loss,once that code appears the compressor will not come on until issue rectified,have you run car with gauges on,if you have what is the low pressure and what is the high at idle and what happens on acceleration. being that you had a code for compressor pressure you may have a compressor that is done. if that is the case do not just replace it the system will need flushing and a new expansion valve which on the GT is a tube type. we did also experience issues with the high pressure switches.just as note if there is a code in the ac control module..9 times out of ten it will shut down the system.all codes will need clearing for the compressor to kick in.

Thanks Mate,
Unfortunately I only have a VAS, I come from the Rally world where air con isn't fitted so I've never worked on or even studied Air-conditioning. The only pressure readings is with the diagnostic function on the VAS which gives sensors and pressure readouts. The only pressure readout was giving 4 bar. :confused:

i would clear the code and see if you can get compressor to kick in, the best thing is you really need gauges to see what is going on, there are many components that could cause no air con.

Thanks, been playing around but cant find the issue. Car goes onto Bently next Wednesday.

I actually got a code today
00229 02
Pressure below lower limit ??


Any advice please?


Fank

Check this thread, D3 A8/Phaeton and CGT's share a lot of parts. http://forums.quattroworld.com/a8d3/msgs/10305.phtml

Cheers :)

Sorry to revive an old thread. Any help would be appreciated:

My CGT has a problem where the A/C will suddenly go out (blower still blows but seems like the compressor cut out). I don't think it's refrigerant because if I put the car away and come back to it a few hours or a day later, the A/C works again no problem with cold air. I can go days sometimes weeks without issue, but occasionally the A/C would stop working again.

Could this be a problem with the compressor pressure sensor transducer? This is the air conditioning pressure sensor fitted to the A/C hose from the condensor to compressor. I've had a look at the threads about the flap motors going bad, but mine seems to still be able to alternate between the two modes just that the air is no longer being cooled but I can hear some flap movements when I press the button so I don't think it's the flaps.

Before over spending on this one. Have an automotive AC service company with an AC manifold pressure gauge check your high and low pressure. Without doing this there is no clear diagnosis.

Turned out it was a compressor. They did the belts and some pulleys while they were in there. And they happened to snap my bumper in half too (apparently CGT and FS bumpers plastic are prone to cracking with age??). It burned a hole in my wallet for sure.

Now the A/C works but it's still not ice cold. They then replaced the restrictor valve and that made it better, but now the problem is back. Wonder if it's worth changing the restrictor valve again - as I heard debris can kill them - so maybe there was some leftover debris still in the system? Thoughts before I throw more money at this car.

I'm getting the flap motor code too, but not sure if that has anything to do with it. I thought it only affects whether I can recirculate the air when it stinks outside - but please correct me if I'm wrong.

A couple things catch my attention. The receiver drier should have been replaced. Some of the debris is captured there and because it is a condensate trap as well normally with compressor replacement it gets changed. After compressor failure compressed nitrogen needs to be passed through the system to expel debris. Additionally a permanent inline filter is installed to catch any residual debris. Again a high and low pressure reading needs to be taken to see what's going on.

This is standard operating procedure on automotive HVAC.

They replaced the receiver driver (the thing that looks like a thermos) and they said they cleared out the system though I don't know using what. They've recommended I change the flap motors since they saw a fault code for them. Just hope that's correct.

You can check the flapper motor. Start the car and look down inside the plastic windshield screen with the hood open. The flap will be in the open position then go in the car and turn on the recirculation button it should now be in the closed position. The internal vent positions are easy to test by changing the settings and seeing where air comes out. I'm sure you know this already.

I'm not sure if the B air conditioning system is the greatest. Mine adequately cools, I wouldn't say it sets any cooling records. My other cars seem to cool quicker.

I had AC issues, ended up replacing the compressor. I got a new one from Denso instead of Bentley as much cheaper for the same part. Also changed the restrictor, drier and AC rad. It's as cold as you like now.
With VCDS you can check the function and see the various pressures etc.
Original post below.

Replaced the compressor on my 2004 GT with one from Denso (I believe Denso manufacture the original compressor) the part number is DCP32052 it's much cheaper than the same part from Bentley. Also replaced the drier, condenser and restrictor valve.

I opened up the cowl and saw the flaps twitching open and close repeatedly. And I now know what's that electronic motor noise I randomly hear from the inside the car now. will keep all posted. Hopefully it's just as simple as this.
I've also done compressor, drier, and restrictor valve. I'm hoping the condenser doesn't need to be done.

The only time I've ever replace a condenser is it leaks. Although they do get plugged up if the compressor puked it's guts. This is why a pressure test on the high and low side is necessary. The restriction will show a high high pressure in relationship to the low pressure side.

Just as a for what it's worth: A couple weeks ago I posted on a flying spur thread my 2007 GT's AC seems totally dead... compressor not kicking on. So just this morning an AC buddy of mine and I checked the system pressure and that seemed fine. So we checked for codes with his Snap-on system... I had my VAG system with me, but we used his Snap-on system. Anyhoo: He asked if my check engine light is on? "No ('cause it isn't/wasn't). He said there's a code showing "no cooling fan signal". I explained the radiator cooling fans seemingly work. He cleared the code... we started the car, and "viola", the AC compressor kicked on, and the AC functions seemingly as normal... blowing nice cold air. The radiator cooling fans kicked on. I cycled the "ECON" feature of the AC control per the infortainment system and that kicked the compressor off... and kicked back on when I took it off ECON. Everything seems to be functioning fine, now.

Wow what a fantastic result ... :)

Update: The car wasn't keeping the cabin cool enough on the really hot days. Even when set all the down to "Low" and manual recirculation ON. Pressure readings were apparently normal. The replacement of the fresh air/recirc flap motors did nothing - additionally they are still twitching between open/closed positions! They reassured me the system had been previously cleansed out, but when they checked the restrictor valve again - it was completely black despite only having been replaced a couple months ago (and it's only been driven maybe 5 or 6 times since then). They recommend condenser placement now - seems like the only final thing to do? Or else I'll be going through restrictor valves every month.

In general an after-market inline filter is necessary once a compressor fails. Would recommend quarrying if it is possible on a Bentley. One of the ensuing problem of a failed compressor is the continuous debris in the system. I would be concerned about the receiver drier being contaminated. We realize it was just changed. With a heavily contaminated system everything had to be replaced. The proper procedure is a complete flush which isn't possible at all AC Service facilities.

What is the proper way to flush? I asked again and Seems they didn’t use nitrogen as you recommended. Just normal air. Given the level of contamination (blacked valve in such short time) any suggestions what should be replaced again? Thank you. I take it I should hold off on the condenser replacement?

just out of curiosity how come a failed compressor causes the debris?

https://cimg3.ibsrv.net/gimg/www.6sp...563c551855.png
This is an example of a type of a professional flushing product. An experienced HVAC automotive shop would have an integrated flushing system beyond what I posted.

The compressor has to be disconnected during this process because it does not allow passage through the other components. Normally it is not necessary to flush a new compressor. However your compressor is contaminated due to the debris circulating through the system. Therefore the compressor should be flushed which is another process.

The best thing to do is call around and find a dedicated Automotive AC service shop. What this means is they go beyond just basic freon service. Many independent automotive shops are not qualified in total HVAC service. A dedicated automotive air conditioning flushing system is very expensive. The independent shops are able to change the components as you found out but they sometimes miss a few steps. Some of the topshop's will subcontract the flushing and filling of the system out.

At this point if everything isn't checked the problem will continue. Whoever performs this service mention that the receiver / drier (even though it's new) could be compromised.

I feel for you. This is not a pleasant problem.

Yes wait until someone properly flushes the system.

The compressor failure that contaminates the system is when the piston and the cylinder walls mesh. Small pieces of aluminum and debris start to circulate in the system. Certainly there are other reasons but that's the main one.

Discuss with your HVAC person if they can install an inline filter. The inline filter is an insurance policy.

Short of a proper flushing and a new receiver drier(?) there is risk of improper function. Unfortunately this is not a Magic Bullet project.

Thanks so much! Looks like my garage has never even heard of this fluid let alone obtaining an aftermarket filter.

I am really frustrated and a bit helpless now - I've been asking around and I suspect only the dealer knows how to do it. I'm reluctant to go to them because Hong Kong dealers are ridiculously more expensive than North America (they quote US$4,000 for a regular oil change). Which is why I've started to go to an independent specialist who fixes a lot of Bentleys. Sadly I find Hong Kong's industry lacking in a lot of skill-set for things we take for granted in North America (e.g. It took me months to find a shop that could refinish a brush aluminum lip, and literally only one or two shops that know how to do "Dent Doctor" repair).

No engine removal. They access from the front - bumper, radiator, those come out.

Rico, I think it's like forum spam lol. That wasn't the OP that posted that. I guess someone is going around to different sites trying to draw up some business.

At the very least it's advertisement on a forum