Air con question

[wizard]

Hi guys (are there any of the fairer sex on the 944 forum?)

I have recently had a retrofit done on my air con system converting it from R12 to R134a. Prior to this the air conditioning would not operate as there was only 45% of the gas left in the system. The system was tested for leaks before conversion so it seems that the loss of gas was due to age.
I have read elsewhere that if the system is not fully charged or operated for a long time the compressor clutch is likely to seize, so I was pleased when I felt a nice icey breeze coming from the vents.

Question
- does the air con switch itself off when the temperature setting on the dial is reached?
- I have also noticed that the aircon will only work intermittently i.e starts and operates for 5 or 10 minutes then stops blowing cold air, hence first question.
- Sometimes it will not blow cold at all and the I cannot see any gas flowing in the inspection window.

My worst fear is that the compressor is actually being tempermental and needs replacing, or recon if possible. Before I go down that route is there anything else that could be causing the above issues?

TIA

Jason

 

[Diver944]

In an extreme case of pedantry (thanks for the word Thom []) we should refer to it as climate control and not aircon because it should try to achieve whatever temperature you set the dial to. Once the car has cooled to the setting it will then switch on and off at will to maintain that temperature, apart from when you activate full throttle when it will then disengage to give you more power to your right foot []

It does sound as if something is not right if it switches off totally after 10 mins. How long ago was the conversion done and did it involve all new seals because I have heard of some that just use the new gas (and new filler valve) which is then prone to leak through the old seals?

 

[Diver944]

ps Mrs Diver is on the forum but she rarely posts as we are always going on about car stuff?????

 

[wizard]

Thanks for your reply Paul.
The air con .... sorry .... climate control[] was serviced a couple of weeks ago by a mobile service. I was not around when it was being done and I can only assume that it was regased and a new filler valve supplied. I have not seen any signs of a leak yet, or would I ?

 

[944Turbo]

The temperature sensors - one outside 2 in? that provide feedback for the climate control could also affect the operation. I know that they do fail on occasion, but do not know much more than that, fortunately not having had one fail yet. There is also the pipe that goes from the small grill beside the clock to a fan, this has something to do with the temp sensing as well.

Tony - being a bit vague this morning

 

[Guest]

I have read elsewhere that if the system is not fully charged or operated for a long time the compressor clutch is likely to seize,

Can't see why; if the system is not used for a time, then the seals can dry out, and start to leak. Also, the oil in the gas acts as a lubricant to any internal moving bits. The clutch is just switched on/off electrically.

The clutch should switch off when the temperature has been reached.
My a/c switches off every so often, for a short time, to let any ice etc. that has condensed on the evaporator to melt, and the water run off - hence the puddle under the car.
But, my car is 3.2 carrera, with internal evaporator, so the finer points of the system may be different; the clutch operation should be the same.

 

[wizard]

Thanks all for advice so far. I had a quick check yesterday to see if the compressor was activating. I believe this is on the bottom right of the engine. It seems that the switch is intermittently activating it or there may be a pressure issue. I remember that the technician said he had to release a bit of the gas to get the system to work initially.
I'll keep the thread updated of any developments.

cheers

 

[Guest]

With my system, if the gas pressure drops below a certain level, a switch then stops the clutch activating, so no compressor operation. Protects the compressor, as there would not be enough oil to lubricate it.

Great way of telling when my system has lost gas !

 

[GPF]

Hi Rohan,

Yes, it should work absolutely fine - well worth getting it looked at.

 

[TTM]

If you expect it to perform with the smoothness of a modern air con then you are likely to be disappointed.

I hardly ever use it in the S2, just the vital minimum to keep it functional, but I loathe how it robs power from the engine.
When switching it on at speed it feels like a parachute brake.

When the compressor clutch engages, the engine vibrates so much it's embarassing.

I'm glad I got rid of it on the turbo while there was no engine in it.

To cut short, it's rubbish. In my opinion.

 

[barks944]

I wonder how easy it would be to swap the compressor over for a more modern one?

 

[tref]

ORIGINAL: barks944

I wonder how easy it would be to swap the compressor over for a more modern one?

I believe Coolit do it as aftermarket fitment/cheap fix option anyway.

 

[Frenchy]

Mine was ice cold when regassed ??

 

[GlennS]

Seems reasonably effective on my S2; as effective as the system on my Golf IV anyway. There's a bit of a whine/moan from the compressor clutch at specific RPM but that's transitory. At idle speeds the only noticeable difference is increased noise from the cooling fan. At road speeds I haven't noticed any significant power drop from having it running.