Aircon not working diagnosis

[anditsoundslikebells]

I've probably not used the aircon since the engine&gearbox was out in Poland.

Maybe something to do with these lads when putting the car back together, changed some settings or software possibly and used generic A6 settings?

I was thinking the same. But I guess they shouldn't have needed to reconfigure anything aside from the transmission. One day I'll buy a VCDS and then I can check everything myslef.

[steve2003rs6]

Don’t know how I went so long without VCDS. Now I think they are a must have for enthusiasts of these cars.
Bought mine from a site member.
Which reminds me. Thank you chunky79.

[Human Joist]

Hate to hi-jack the thread. But it’s been done a few times to me so all fair in love and war

My air con seems to take ages to get cold. I know it was hot today but took about 20 mins to get proper cold. New compressor last year and re gas etc. No codes on VCDS. Is that normal or am I missing something.

I also get quite a bit of wind noise from the bottom of the screen, not sure if that could be linked. Searched the forum and can’t find anything

[Shoppinit]

Could be a blocked dryer. Or over gassed. Or under gassed.

As for the windscreen, there have been a spate of people with replaced windscreens that are too short and don’t seal properly at the bottom.

[Shoppinit]

E.g. viewtopic.php?f=2&t=139424&p=950052

[Human Joist]

Cheers Shop. Will check the screen and the gas at garage. What’s the blocked dryer issue ?

[Shoppinit]

The dryer should be replaced any time the AC circuit is opened. It filters the crap / dehydrates the gas. If it gets blocked then it'll restrict gas and oil flow and you'll get poor AC performance and increased compressor wear.

Was it replaced when your compressor was? Most manufacturers won't honour warranty on compressor if you can't prove you changed the dryer at the same time.

If it was a back-street AC re-gass, maybe the moisture wasn't pulled out properly with a decent vacuum pump. Who knows. AC is voodoo. I hate it.

[Nobby]

Another jumping in the bandwagon.

My aircon doesn’t seem that cold. It’s ok when it’s around 23 degrees but when it’s 30 plus it’s just doesn’t get super cold.

I had it regassed a few years back but it’s not low. Also got a gauge kit and from what I remember both my high and low are normal. I’ve done various things so far, cleaned out the condenser, reset the flaps, checked the drain hole isn’t clogged. Both fans are also working and compressor is kicking in.

I’ve not the bullet and just bought a new high pressure switch which I’ll change first (it’s got a shrader valve so seals when it’s removed).

Also got a new drier and expansion tube. I’ll need to take it the garage to get all the old refrigerant vacuumed out first).

I’m tempted so see if the evaporator is gunked up and clean with my steam cleaner but might try that after the switch.

I did look for a new condenser but genuine are mega expensive. Compressors aren’t that bad. Just hope it’s not the evaporator….

[Shoppinit]

No reason to change the evaporator or condenser if they are not leaking.

If the gas pressures are good (did you check while the engine was running and calculate for temperature?) on the low and high side when the engine is running (and when not) then you could have a clogged drier or maybe your clutch on the compressor is worn and it isn't being spun up enough. This is the problem I have on the Volvo currently. Not sure how easy it would be to see on the RS6.

https://i.imgur.com/SYIFjCC.mp4

[Shoppinit]

Another common problem is that the AC is fine but the flaps aren't moving properly inside the HVAC and it's mixing with warm air.

[Human Joist]

I swapped out the compressor myself then took it for a re gas. I didn’t know about the dryer till i read this.

To be sure I will get the gas changed so I’m happy it’s sorted and was emptied properly as it hadn’t worked for ages till fixed it.

Can you tell me where the dryer is etc so I can swap that out as well prior to the re gas. The car has done very minimal miles since so hopefully won’t have damaged anything.

[Human Joist]

Another common problem is that the AC is fine but the flaps aren't moving properly inside the HVAC and it's mixing with warm air.

Is there any links to stripping, checking and fixing this

[Nobby]

I’ve checked the flaps and they are as open/closed as they should be. Yeah even disconnected the flap motors and moved them by hand.

My only worry is the evaporator is blocked - either internally or externally with leaves or gunk.

[Nobby]

HumanJoist - the receiver/drier is the large ally cylinder the the left of the engine bay. It has 2 connections going to it with one rubber and one hard pipe. Looks like a big fat coke can.

[Nobby]

Like this

https://www.autozone.com/cooling-heatin ... 797509_0_0