DIY car A/C freon top-up

I’ve seen cans of R134a in car accessory shops, but no obvious way to transfer the canned freon into the shraeder valve on car’s A/C system.

Anyone know where to get a magic hose to do this?

[quote=“monkey”]I’ve seen cans of R134a in car accessory shops, but no obvious way to transfer the canned freon into the shraeder valve on car’s A/C system.

Anyone know where to get a magic hose to do this?[/quote]

Sorry, dunno.

I think the expert opinion is/was that a top-up at an aircon service place was cheap enough that DIY wasn’t worthwhile.

How much were the canisters?

As an aside, this source has:-

[i]"Latest Development

The recent discovery that R-134a contributes to global warming has caused the European Union to ban its use on new cars starting from year 2011. Other countries are expected to follow suit.

Taiwan of course isn’t bound by any agreement that might emerge, since they don’t exist, so can’t sign anything.

OTOH, they do, for example, voluntarily observe the Montreal protocol on CFC’s, so this stuff might disappear off the shelves eventually, but since it refers to new cars I guess it’ll take at least 10 years.

There are lots of different brands. All the cans are about the same size, maybe holding 1 liter of R134a. I think they are about NT$400 or so.

Okay, the correct way to load your gas into your air-con system is with professional gauges and a high powered vacuum and pressure pump

Firstly, if your gas is low, then do you know if you have a leak or not?
Do you know how much existing pressure is in your system?
Do you know how much lubricating oil is left within the system?
Do you know if your air-conditioning pump pressure valve/switch is operating at the correct pressure?
Do you know how much gas (weight or volume) your system is supposed to be charged with?
Do you know the last time your filter cartridge was replaced?
If you have a pressure leak, then do you know how to locate it?
How do you know that your gas has leaked out and that you don’t have a fault in the system?

These are just some of the questions and issues a novice will face, and which will more often than not cause them to destroy their air-con system and cause even more cost than if they just approached a professional in the first place.
Trust me here, we deal with these things, day in and day out. DON’T attempt to fiddle around with your air-con yourself! Without good experience with this system, then you’re going to make it worse. The chance of making it better without the proper equipment and knowledge is almost nil.

Well I reckon there’s a 99% percent chance that adding some freon will fix the problem.

But there’s 100% chance that if I take my car to garage, some helpful mechanic is going to start tearing into my A/C system (to measure the oil, check the pressure, cast a good luck spell on the compressor, add gas dye and finally add some fucking freon) that I will be stiffed with a huge bill 10 times what it would have cost me if I have just added the freon myself.

As I recommend, and which of course you are free to ignore, the adding of refrigerant as simple as that sounds, with no equipment, is possibly going to work, but not likely to be economically effective.
A garage will typically charge you around 1,000NT for a re-charge. Your air-con system is worth many more times that price in repairs once you have reduced its effective life-span by not properly going about the business of it’s maintenance.
A garage such as ours would not even charge for another re-charge if the first re-charge wasn’t successful, if the vehicle still exhibits signs of a fault.

I don’t recommend people go about learning this the hard way.

There are reasons that garages have professional equipment to manage such maintenance and repairs. It’s not simply so that they can flash some gauges around so that they can charge “10 times” the cost of jamming some bottled gas at whatever pressure into your fragile air-con system.

Sula, I don’t think these things are as fragile and mystical as you make out. All older cars tend to leak some freon because compressor seals wear, o-rings in pipe unions harden and crack over time, and specks of dirt gets stuck in shraeder valves. So long as you monitor the air temp coming out of the dash vents and add the freon very slowly, you can get the freon charge almost spot on. Too little or too much and the system efficiency goes down (air vent temp goes up).

Of course there is a need to professionally examine the A/C system if it’s showing symptoms of anything other than low freon.

Anyway, even if it all goes wrong and the compressor grenades, I have a spare sitting in a box somewhere. :smiley:

That’s fine. You are of course entitled to your opinion.
I only work with these things all the time.

I’m on the edge of my seat here. Please share with us all the details if you actually decide to go ahead with topping up the gas with a garden hose in a parking lot :pray:

Unfortunately, I can’t do anything without a tapping valve for the freon cans. They look something like this:

I’ve seen it alleged (on a US-based discussion forum) that automative air conditioning shops just discard the empty cylinders their coolant is supplied in.

Anyone know if this is true in Taiwan? I could do with a pressure cylinder, able to take, say 100 psi, which would give a reasonable safety margin operated at up to 50.

A small propane cylinder might also work, or for a very small unit, I could use a “pipe bomb” style construction. I can get the bits for the latter, but it gets quite expensive at the sizes that I’d need.

[quote=“monkey”]Unfortunately, I can’t do anything without a tapping valve for the freon cans. They look something like this:


Any chance these might be useful?

I’m not sure what they’re for, since the English is covered by the price sticker, as is usual. They look like air line adaptors.

car_related_03_08_2012 by ed_lithgow, on Flickr