Air con problem mk5 R32

[Yowza]

Hey everyone, just got a question regarding the air con. I have an Golf mk5 R32 & it looks like the air con is on its way out or already done. Not sure if it's the compressor or a leak somewhere though.

Bit of a run down;

1. I'm on the southern end of the Gold Coast, got a local mobile air con 'specialist' to come out to my place and see why the air con wasn't working and the vents were making a hissing sound from the vents with the air con switched on. He tested the pressure and said it was very low on gas. So I asked why this would be, has the compressor failed, is there a leak etc? Got a response of "it's a 5 yr old car, the gas used these days leaks slowly through the rubber hoses...blah blah blah". I knew it was more than that. Anyway the air con was working and did so for about 3 mths, then it goes again. Same hissing noise.

2. Get the guy back out and tell him it's done it again, he gets his pressure testing gear out and has a look, asks how do I turn the air con on? Told him press the AC button (I'm starting to really question myself about this guy at this stage, but he's old & supposedly has over 35 yrs experience! He looks under the bonnet and says the compressor is not engaging, I can't put more gas in because it needs to engage to be able to fill it. I ask why has it leaked again so quickly. Guy gets frustrated, says nothing he can do, jumps in his car drives off. I stood there dumbfounded at this bloke for awhile.

3. Took the car for a service at VW South Tweed, get them to check the air con. Lady at reception tells me they refilled the gas and put the dye through it. If it happens again bring it back and we'll see where the leak is. This was about 2 weeks ago.

4. Noticed there is a small puddle of water (im guessing condensation) just in front of the front wheel on the floor. Tried to look under with a torch, but the wheel arch guards are covering the area. So there has to be something leaking somewhere. Also air con is not cold, but also not making the hissing sound out of the vents at this stage.

Now to the question, is there a good QUALITY air con specialist on the Gold Coast or Brissy? I know if I take it to VW they will say we can fix it, but the compressor, dryer etc need to be replaced, that'll be 2k+ thanks.

Has anyone else had this issue? I searched the forums using the search function, but it brought up 100+ topics for all sorts of things.

Sorry for the long post, but any help would be much appreciated

[simple_man]

Mine was not cooling much. Tested - low on gas. Regased - tested still low on gas.
Compressor not generating pressure difference. Assumed the worst: compressor failed (known problem on R32) sensing metal thru whole system. Quoted in Brisbane - up towards 4-5K to get all sorted.
Purchased new compressor, condenser, drier and special OIL ($400!!!) for compressor.
Swapped the lot - working fine. Parts shipped from BMA in USA, costed about $1000. Another $500 labour...

Working OK till date. I suspect that all that failed was a presure bypass valve on the AC compressor. As I taken old compressor apart and hound no mechanical issues....

[HaydEn]

Wasn't the compressor a across the range mk5 problem in the first year models?

[simple_man]

That was what I have learned. There are two models of compressors R32 MKV came out with Zelex/Valeo - bad choice by VW. They later changed back to better quality Sanden brand. Mine that failed was Sanden, a better unit.
My R is 2006 or 2007 model, do not remember....

[Umai Naa!!]

Sandens were the worst for failing. They switched to Denso units after that.

Another common problem is the refridgerent pressure sensor leaking through the connector plug, and into the wiring harness. A tricky one to pick up on.

[Yowza]

Thanks for the replies guys, appreciate it!

Umai - do you know the location of the pressure sensor? These cars have no room under the bonnet to see much. I've tried searching around behind the drivers side headlight area for leaks, but can't see much at all.

I have a feeling it's something along those lines as when the gas is full the air con works a treat & is 15 degrees celcius on lowest setting. But as the gas is lost I assume that the compressor does not engage so as to no destroy it.

Will try to find someone on the Gold Coast to take it to next Wednesday.

[Umai Naa!!]

Spot-on. It wont run if the gas is too low.

The pressure sensor is just above the right side chassis rail, next to the fan.

It's difficult to get at on a 4 cylinder Golf, so I don't know what chance you've got with the VR6 motor in there.

The temperature you're aiming for with it on recirculation, on the face position, at the centre vents, with the fan speed somewhere in the middle, is around 4deg C. Best measured with a thermometer down the vent.

[jessv3]

Sandens were the worst for failing. They switched to Denso units after that.

Another common problem is the refridgerent pressure sensor leaking through the connector plug, and into the wiring harness. A tricky one to pick up on.

Do you know what year model they switched to Denso?

[Umai Naa!!]

No idea. All replacement units are Denso, though.

[Yowza]

Thanks Umai, I'll try find the sensor when the wife gets home with the car today, but like you said there's no room to move with the vr6. I thought I'd give the air con a shot yesterday & it was just blowing 'normal' air (i.e...not cooled via air con) and then I hit the auto button on the climate control and it kicked it, had it on 22 degrees and seemed to be working fine. So would that indicate that the compressor would be ok & that there is some kind of problem with the pressure sensor? I take it if the compressor goes that the air con would no longer work at all?

I'm hoping that it's something cheap like the sensor gone compared to the compressor etc

Will still be taking to an air con specialist this Wednesday, so hopefully if there is a leak he'll see where it is with the dye that was put through it.