zanglezonker

I have a recently purchased 92 Civic LX.

The AC doesn't work.

It's been "converted" from r12 to r134a, but I don't know if the "conversion" involved removing the r12 and flushing the oil, or just adding adapters to original valves and topping off with r134a.

Presently the system leaks. I added a large can of r134a and the pressure was back to zero within 15-20 minutes.

I plan to get the leak fixed and have the system flushed, since I don't know if there is a mix of oils in there now.

My question is whether to switch back to r12 or refill with r134a? In particular, I'm wondering if anyone can tell me if the factory 1992 AC hoses are barrier hoses?

More broadly, are the hoses and seals and other equipment compatible with r134a?

If not, would they have been *damaged* by r134a, or can I just flush the system and start over with r12?

(As to the cost of r12, I'm in San Diego and can have the car refilled in Tijuana).

Syndacate

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by zanglezonker &raquo;</TD></TR><TR><TD CLASS="quote">I have a recently purchased 92 Civic LX.

The AC doesn't work.

It's been "converted" from r12 to r134a, but I don't know if the "conversion" involved removing the r12 and flushing the oil, or just adding adapters to original valves and topping off with r134a.

Presently the system leaks. I added a large can of r134a and the pressure was back to zero within 15-20 minutes.

I plan to get the leak fixed and have the system flushed, since I don't know if there is a mix of oils in there now.

My question is whether to switch back to r12 or refill with r134a? In particular, I'm wondering if anyone can tell me if the factory 1992 AC hoses are barrier hoses?

More broadly, are the hoses and seals and other equipment compatible with r134a?

If not, would they have been *damaged* by r134a, or can I just flush the system and start over with r12?

(As to the cost of r12, I'm in San Diego and can have the car refilled in Tijuana).
</TD></TR></TABLE>

I don't know much about AC systems, only that I've changed way too many AC compressors in my VW Jetta, and I've did the whole AC maintenance thing a few times (compressor, condenser, expansion valve, etc.).

If your system was a legit conversion to r134a then they should have swapped the freon out and put in the r134a. You do the same, put in r134a, not freon.

There's a reason they're two separate systems, they're made to run on two different oils, now if they were interchangeable there wouldn't be a conversion for it, would there?

geebs

the hoses should be fine.. theres a difference in the chemical breakdown between r12 and r134a.. they do require different oils.. but the oil will come out when you evacuate the system.. a retrofit kit changes the valves to quick connects.. id have the system vaccuumed to remove everything from it.. then charged with r134a and dye.. most a/c oils contain dye now anyways.. then just get a black light or uv light and check for leaks.. it usualls leaks from the couplings with o rings..
dont charge with r12.. its not only illegal now but also kills the ozone.. dont be a killer! r12 has chloroflorocarbons.. cfc's.. read a can of brake cleaner.. theyre allow to have cfc's either..

strategy400

I had a 92 Accord which I converted to R134a. It was holding a weak R12 charge when I made the conversion, so I figured it had a very very slow leak. I had a shop evacuate the system and pull a deep vacuum. It held the vacuum ok so I charged it with oil and 134a. It worked OK for about a day then had the symptoms you describe (total loss of gas in 15-20 minutes).

Jonathan_ED3

Make sure you change the drier too.

I very seriously doubt if the system was swapped over properly. They probably went to a local auto parts store and bought the DIY R134 swap kits, which as somebody already mentioned are just the quick connect fittings.

The kits tell you to have the system evacuated but nobody ever actually does that...

zanglezonker

First off, without any information, I have to assume that the "conversion" was done by installing a kit from the corner auto parts store without following the instructions to remove the r12 and the mineral oil (i.e., that it wasn't "legit").

My understanding is that not only does mineral oil fail to circulate in a system filled with r134a, but also the lubricants used with r134a tend to coagulate when mixed with the mineral oil used in r12 systems (or so I've read).

Second, it is legal to use r12. You have to have an EPA license to handle it in the US, and it is ridiculously expensive here. It is supposed to be available b/c any that is removed is recycled, but in reality a lot is smuggled in from Mexico.

So it would be illegal for me to go to TJ and buy a case and bring it over the border in my trunk. It would not, however, be illegal to have my A/C serviced in Mexico and drive it back to the US.

That said, I found the answer to my concern about the barrier hoses on the EPA website:

"When R-134a was first introduced, it was thought that all non-barrier/nitrile hoses would have to be replaced during an a/c retrofit. Early laboratory tests showed that the small R-134a molecules leaked through the walls of non-barrier hoses more readily than the larger R-12 molecules did. In the lab, this caused unacceptably high leakage rates. More recent testing, however, has shown that oil used in automotive a/c systems is absorbed into the hose to create a natural barrier to R-134a permeation. In most cases, the R-12 system hoses will perform well, provided they are in good condition. Cracked or damaged hoses should always be replaced with barrier hoses."

http://www.epa.gov/ozone/title....html
(which is a good guide to the retrofitting issues).

So I'm planning to get the leak fixed and the system flushed and fill it with r134a. I'll probably try to get it lubricated with ester oils that are also compatible with R12, in case I change my mind next time it need service.