A/C Conversion from R12 to R134

[bgator]

Here in the South, it's time to get the A/C working. I just put in my last can of R12 and I'm sure that it will need more as summer rolls around.. I was wondering if anyone has made the conversion over to R134? Is this something that I should try myself, or bite the bullet and put Gertrude in a local shop for a pro to do? As usual my money is funny and I need to stretch every dime. I do not own the necessary guages etc., but have access to them at the high school where I teach. Any and all advice is welcomed!! I really don't like sweating while driving, even with the windows down, it's danged hot.
I've googled and researched the web and have found all sorts of info but nothing pertinent to my beloved VW. Please pipe-up to help me keep my pipes cool.

[bscutt]

I converted an 81 diesel Dasher wagon a couple of years ago since I bought it with a broken high pressure hose and it was of course empty. Had a hose made and drained all the compressor oil out of the compressor. Filled the appropriate amount of the new type compressor oil and closed it up. Evacuated the system and recharges with 134 but had some problems getting the pressure right. Consulted my mechanic and ended up letting a good bit back out and then it was fine (high pressure had to be under 165 at idle if I recall). I did not do the whole routing recommended by the professionals which involves flushing out the system a couple of times, replacing the receiver dryer, and in some cases they recommend replacing the expansion valve is I recall correctly. Anyway it all worked very well when I was done. I do have a vacuum pump for AC work and the necessary gauges (old cheap JC Whitney ones if I remember) but all was suitable to get things running well.
To be honest I sold the car a short while later so I can't tell you if it was a good long term solution. There are some good write ups on line for doing the conversion and they vary from just refilling with R134 (not a good idea and not likely to last long) to the full purge, replacing hoses, compressor oil, expansion valves, condenser, and so on. I have worked hard to keep a stash of R12 around for my vehicles that use it and nothing leaks appreciably, but it's getting pretty expensive to buy the R12 and people around here sell the old small cans of it for as much as $25/can. If you can find a way to stick with R12, do it for as long as you can.

[bgator]

Thanks Bob

I did find a local parts store that still has a case of r12 and is willing to sell it under the counter so to speak for $22 per can. Kind of pricey but that should keep her cold for several years.
Did you have to remove the compressor to get the old oil out when you converted? Or, can it maybe be blown out with air pressure?

[bscutt]

Well I kinda cheated on that - when I bought the car the lower hose on the compressor was the broken one and it broke right at the fitting. It had been driven that way for a little while so I was pretty sure most of the old oil was out so no, I did not remove it. Not sure if you can blow it out effectively. Definitely lay in some safety stock of r12. I paid over $150 for my last half of a 30 pound can of it and am being miserly with it. That was a good price.

[diesel freak]

I had my 86 Golf Diesel converted by a professional air conditioning shop. They replaced my compressor and dryer but it still would not cool. Than they replaced my fan with a dual fan system and it ended up costing me $1200 dollars. It worked great for one year and I can no longer afford to put any more money into it. It may just may need an additional can of R134 but the summer has been mild so I just drive with the windows down for now.