A/C operation?

XantiaMan · Post by **XantiaMan** » 27 Feb 2008, 17:40

Just preparing for the summer, doesnt seem to working, like its low on gas, you can hear it hissing behind the dash on and off, and also if you look at the clutch you can see it engage and disengage around idle speed. Just wondering if its simply low on gas? It worked perfect in the summer and i occasionally press the AC switch but probably not enough to maintain it.

Gareth

Stempy · Post by **Stempy** » 27 Feb 2008, 21:19

Have you checked the sight glass on the drier bottle? If it shows cloudy or frothy refrigerant then it may need a regas.

XantiaMan · Post by **XantiaMan** » 27 Feb 2008, 21:30

Stempy wrote:Have you checked the sight glass on the drier bottle? If it shows cloudy or frothy refrigerant then it may need a regas.

Yes you can see its cloudy when the pump turns on, i refilled it myself last year and even after this it was still not clear, but the AC worked great.

alan s · Post by **alan s** » 28 Feb 2008, 02:44

Take a close look at all the joints for signs of what appear to be oil stains. If there are any, chances it will be where the leak is.
Also, with some of these systems, the gas charge even when full doesn't always show the sight glass as clear, but a full load takes around 1kg from empty.

If/when you guys get access to "Greenfreeze" (hydro carbon refrigerants) over there, you'll find it only takes around 300grams to fill the average system.
I struck a job the other day where the sight glass was reasonably clear, the hose from the compressor to the condenser was red hot but no heat from the hose from the condenser to the receiver. It also tended to squeal the belt on start up and got cold for the first couple of minutes after which it went back to room (ambient) temperature.

Problem? A blocked receiver/drier, which shows, they don't last forever.
I would suspect the dessicant inside it may have crumbled and blocked the internal filter. Might cut it open when I replace it.

Thought I'd mention this just for the advice of anyone having problems with theirs that won't answer to reason.

Alan S

XantiaMan · Post by **XantiaMan** » 03 May 2008, 19:01

I'm pleased to say i have working air-con again, for the sake of £20 quid i got another bottle of gas from Halfords, as we as supposed to have a warm week ahead of us. Dont mind topping it up every 6-10 months, it didnt take much to get it working again either!

tricky ricky · Post by **tricky ricky** » 04 May 2008, 14:51

How easy are the aircon kits from Halfords to use. My aircon needs a topup as its not that cool

XantiaMan · Post by **XantiaMan** » 04 May 2008, 19:13

tricky ricky wrote:How easy are the aircon kits from Halfords to use. My aircon needs a topup as its not that cool

Virtually childs play. Undo the correct cap off the pipes, push on and depress the button on the can, with a/c on full blast.

I'm very glad i did get the can yesterday, as today was particulary humid inside the car and with a 2 month old baby, its always a worry they will get too hot. After 5-10 minute blast on full, dropping the fan back to auto maintains a nice even temperature and i'm pleased to say Jack did not look or feel hot at all.

One of the reasons why i got the Xantia was the fact it had A/C, when we got hot days in this country they really are hot and it takes some of the stress out of driving.

tricky ricky · Post by **tricky ricky** » 05 May 2008, 12:11

Went into Halfords. They sell a kit with a gauge for £40. I'll get a quote from an aircon company and see what the difference is.

MikeT · Post by **MikeT** » 05 May 2008, 12:17

I bought that very same can with gauge after the Halfords assistant showed me my gas pressure was a little on the low side. Sure enough, the refill (appx half a can used) brought the A/C temp down to a very effective ice cold 8) but it didn't last - I assume there was a leak somewhere.

I noticed last year that many companies were advertising cheaper A/C services for some reason so I think it's well worth getting a proper full service done every now and again as you'd be wasting money recharging a leaking system IMO.

tricky ricky · Post by **tricky ricky** » 05 May 2008, 16:26

I dont think I have a leak as such. The car is 9 years old and never had an aircon service. Just natural wastage I think. How did the halfords assistant check the pressure? I may get that done.

MikeT · Post by **MikeT** » 05 May 2008, 17:38

Halfords offer a free pressure check, or at least they did last year. They simply use the same gauge you see on sale with the £40 can and plug into the low-pressure port - it's the same method as reading tyre pressures basically, just slightly bigger valves.

Post by **xantia_v6** » 05 May 2008, 19:10

You really can't tell whether an A/C system needs more gas from a pressure test, especially a single guage test. Assuming that there is no air in the system and some liquid refirgerant, a pressure test only tells you the temperature of the warmest liquid refridgerant in the half of the system where the test port is.

The ONLY way to determine whether more refrigerant if needed is to remove the gas and weigh it, or remove the gas and replace it with a known weight of gas.

If the charge is low enough that there is no liquid refrigerant, then the pressure will be unusually low, but by that time, you need to have the system evacualtged and leak tested anyway.

The trick is to find someone with the right equipment who knows what they are doing with a refrigeration system.

MikeT · Post by **MikeT** » 05 May 2008, 19:49

xantia_v6 wrote:You really can't tell whether an A/C system needs more gas from a pressure test....The trick is to find someone with the right equipment who knows what they are doing with a refrigeration system.

Thanks for letting us know. Perhaps someone needs to have a word with Halfords as they are surely profiting from this misinformation

steelcityuk · Post by **steelcityuk** » 05 May 2008, 20:59

I had the AC in the C5 looked at on Saturday, the chap I went to advertised on Ebay, he was an AC engineer but is now a fitter (it pays better appaerently).

He connected up a set of gauges to the car, it showed 10 PSI on the low pressure side (that would be why the compressor or fans wouldn't kick in). He removed this gas then put a vacuum in the system and then turned his vacuum pump off. The car held the vacuum for 5 minutes without it dropping so he said he was satisfied that it didn't have a leak so he turned on the vacuum pump again and left it for 30 minutes to boil off any water and remove any contaminants. After this he put a 'bottle' of R134a onto a precision weighing scale then put a little gas into the system the asked me to start the engine, put the AC on the coldest setting with recirculation and highest fan speed. The AC immediately came to life. He checked the amount of gas the C5 should have (it was between 650 and 700g) he then allowed the AC system to take the gas from the bottle whilst watching the weight. The high pressure gauge could be seen to climb to 250 PSI before the fan cut in, then the pressure dropped to 200 PSI and the fan cut out again. After around 10 minutes the AC system had taken the recommended amount of gas. He tested the air temperature at the central vents, it varied between 3.2 and 3.5 degrees C. Total cost £30!

I asked him about the self fill cans, he called them suicide cans, I aksed why, he said because you have no idea how much gas is in the system, if there are any blockages or other problems. Plus he pointed out that it's illegal to knowingly fill a leaking system with R134a because it's a greenhouse gas.

It was a very interesting couple of hours I spent chatting to him.

Steve.

tricky ricky · Post by **tricky ricky** » 08 May 2008, 17:38

Made the decision to get the regas done properly. It was done by a local auto electrical company for £55.

Aircon is now Ice cold!!! (7 deg measured at vent) outside temp is 22 deg.