Air con needs re gas again?

[gearhead188]

Looks although the air con needs another regas. Blowing cool air but not cold air, has a awful musty smell as well. The pipework still gets frosty..
The thing is...i bought the car from a friend less than a year ago and i remember him saying it had been re gassed. I just checked the history and it was done just over 1 year ago. I have only done less than 10000miles since i have owned it.
I run the aircon all the time to stop the seals from getting dry. So where else can it be leaking from? i have noticed a hissing noise everytime i turn off the engine, but i assumed this is the noise from inside the pipework as the pressure drops...can this be the possible source of the leak?
I really don't waste money on re gassing it only to have it done again.
Any thoughts?

[Izalman]

Hissing noise when stopped is normal - gas settling down in the system.
Get it checked by an independant AC guy, dealerships rarely have a qualified AC guy, they use independants most the time.
He will have the gear to check for leaks, I deal with AC in offices / shops - eexactly thesame principle - there's all sorts of gear to check for leaks - frosting on components is a sign of gas shortage - you may not like the news

[gearhead188]

I had an independant check the system. There was pressure in the system so it looked as though there wasn't a leak. We decided to evacuate the remaining gas and refill to the correct weight. 130 grams came out 500 grams went in (500g being the recommended amount for passats)along with some sealing oil.
On discussion with him, he suggested that AC system will leak slowly all the time and it's best to make the sure the A/C system gets exercised several times during the week. This i knew, but the car hasn't used very much in the past few months so it made sense that the seals may have dried out hence the disappearence of the gas.
Anyhow...
We fired it up to get the remaining r134a into the system and all was well, immediately nice cold air as i remembered...lovely!
Go to the use the car today, and it would appear to have lost it again, just cool air coming out not cold air.......
I've taken the front bumper off and sprayed leak detect solution on the joints but cannot see anything wrong.
Can you tell me how they check for leaks? so far he's only checked the pressure which isn't indicating anything wrong.
When you say i may not like the news, what are you suggesting, a new compressor pump? the cars only done 92000miles !!!!
(damn this modern s**t.....i think i may go back to using my 58 beetle, i only have to set the points on that!!!)

[Panzerdriver]

What system is fitted to your car Climatronic or standard type (manual selection)??

[gearhead188]

Climatic.
The compressor is cutting in because the revs drop.So there is refridgerant.....i got thinking it was the drive belt not tensioned up correctly, it wasn't.... but that isn't the problem. After re tensioning it was still not working.
The lastest plan is for my AirCon man to look for leaks with a UV lamp, if we don't find anything wrong then we go to planB.
Plan B might be to evacuate the system to check the weight of the refridgerant. If it hasn't lost any, then i guess it's the pump not pressuring the gas????
Any air con experts here? I'd love some input....how do you tell if the pump is working?can it be tested? or is it a straight replacement?

[JustinM3]

They do naturally lose up to 20% a year, so that coupled to a very slight leak, you can see where it goes.
Does need a uv light to see where it's going, sure this is your problem.

[chrispassat]

Look under the bonnet with the Aircon selected (auto mode)- can you see that the aircon pulley is engaged?

Check is to see that the integrity of the wiring from under the cowl near the pwr steering filler to the a/c pulley is intact. Especially check the behind the bumper connector, and the pressure switch connectors - they all need to be firmly in (mine were not!).

[blue250]

Hi

Try looking at the refrigeration condenser which is like a small radiator behind the front grill. this is normally made of aluminium and surprisingly can corrode due to salt on the roads or damaged by stones etc.
A gas leak would normally bring with it some compressor oil causing a stain,use a strong torch to find.A mixture of washing liquid and water or a childs bubble solutionwould also help.


Hope this helps.

[gearhead188]

Update on this:
The pump will no longer engage and the climatic control will flash 20secs on start up. Been waiting for the A/C man to come back to check for leaks. I guess this time of year he's much in demand!!
I have already inspected condenser/pipework for oil residue, i find find it hard to believe 500grams of refidgerant+oil have gone and there is no trace, but it's a bit difficult to judge when looking at the pump as it is already covered in oil. However i will wait and see what amount we manage to extract when we evacuate the system and go from there. Thanks for replies

[gearhead188]

A further update:
We have it fixed...at last. And yes it's taken some time to figure out what is happening.
there is a bulkhead fitting (where the two A/c pipe fit into) i reckon i distrurbed them when i removed the battery to clean out the drain plugs. They are held in by a single bolt and clamp. When i removed it and took out the pipes the 2 purple coloured 'O'rings looked disformed. So we decided to replace them before regassing. They were cheap enough from the VW dealer although not kept in stock.How ever this alone did not cure the problem when we discovered it was still leaking As a desperate measure i decided to double up the 'O'rings. This had the leak cured...but it was short livedThe 'O'rings split and i lost the gas once more.
Another week goes by without A/C...this time i am determined to fix it.
I remove the pipes for a further inspection and realise that the rubber mounted bulkhead fitting is sagging downward and this(i believe) is causing the pipe to twist just enough to cause a small leak. One more trip to the dealers and wait for 2 more 'O'rings to arrive...
This time i used a high spec 2 part sealer and coated the pipes and 'O'rings, bolted the pipework back, let it harden and get it re-gassed for the last time.
5 days later it's still working ok
Luckily for me, the A/C guy has been really kind and although i have had to pay a bit more than was originally quoted i still have only shelled out £60 (he's actually visited me 4 times!!).
So i have posted this to help out someone who may find themselves with the same problem and save the grief i had to deal with.
Hey!!!!...... who knows we might get a summer now???....bring it on