Car is a 92 Civic sedan with original AC parts, minus the compressor that was missing from the car when purchased. The parts I'm gonna buy new are the compressor, filter drier, condensor, expansion valve, and all new green o-rings for all connections. I also plan to flush the system with the special tool and liquid designed for that, since the system has been open for years. My questions are: should I replace the evaporator as well or should it hold up fine? Can I find an R12 filter drier and use it with R134a refrigerant? If I have to use an R134a filter drier then what Civics have compatible piping I can swap over?(R12 filter drier has different piping fittings than the R134a ones).

 

I would also replace the evaporator just because.

OEM parts have lasted for a quarter of a century or more.

Sounds like you already are well versed and know what you are doing. I do know you have to stay with whatever refrigerant the car came with, you cannot upgrade to a newer refrigerant as the parts were not designed for it and won't last is my understanding.

 

I don't think that's true at all. I've converted about 6 cars over to R134a, never had an issue.

Primarily simply needed the adapters

Then I needed to make sure I had all the seals in good shape.

https://itstillruns.com/convert-r12-...m-6616048.html

Should be a nobrainer.

 

You know, you caused me to pause and reflect and I'm beginning to wonder if my memories are crossing a bit and the conversation was regarding our house AC and something about the evaporator being a different size and such for the new refrigerant and that the older isn't available anymore etc etc.

Thank you for causing me to reflect more scrupulously.

 

Ah, now you could be onto something there. House AC could be very different.

For most "modern" cars, it's been consistent across the board. 1989 camaro, 1990 Civic, 1988 Mustang, etc 1980's and 1990's car mostly, with a 1979 truck thrown in. All good.

But, you do make me think that it might be an issue if you go back far enough, especially those really older style big unwieldy compressors, like a 1960's car, maybe even a 1970's car, especially before 1975, might have an issue. On really old cars, we usually just switch it to Vintage Air.

It's funny we were talking about it, today I helped a neighbor with am 1984 or so S-10 truck (I think that's the right model) put on adapters and fill up his car with R-134a. We were even sure if there were any leaks to address, but it filled up and started working immediately.

 

It could also be a country thing. If I recall the tech was saying the refrigerant in our AC isn't available any more so if they have to go to the new they have to redo the portion above the furnace, which I think is the evaporator as the new refrigerant needs bigger ones, so some tin work would need to be done. And if we get lucky the AC company might have some of the older refrigerant left hanging around they can top up with etc but yeah.

So it gets me to thinking it could be an environmental policy put in place for BC Canada or all of Canada sort of thing. I honestly don't remember which refrigerant it was but I do know there is newer more "environmentally" friendly options being pushed now a days and it ain't that. :D

I believe I was associating that conversation with the vehicles just because I know they are using older refrigerant. It's good to know my initial recall and thoughts were wrong.

 

Thanks, I'll go ahead and replace the evaporator as well. I was leaning towards that direction but I try to avoid replacing the original Japanese parts with new Chinese or Taiwanese parts if possible, since the OEM parts are so well built.
As far as your home AC, the old systems used R22 refrigerant and the new systems use R410a. R22 is ozone depleting so new manufacturing of it is outlawed and only existing R22, whether new or recovered, can still be used. R410a contributes to the green house effect, so it's still bad to release it in the air, but it's better for the environment than ozone depleting refrigerant so that's why the switch was made. Also, R410a operates at a higher pressure than R22 so that may be why home ACs can't be converted. I did a lot of research when I installed my mini split so that's how I knew about the refrigerant info. I just need to learn more about repairing old ACs :-S

 

You would do well to read this, if you're planning to change the evaporator, in order to add a cabin filter!
https://honda-tech.com/forums/honda-...civic-2552431/

...holy crap, I wrote that in 2009.

 

The problem with all AC systems is that most don't properly evacuate all the moisture from the system.

When R134a is exposed/mixed with moisture it will become acidic and eat away at the system internally. This is the biggest reason for evap coils failing. I've usually put a vacuum pump on the system and let it pull for about an hour and then record the vacuum gauge reading (should be about -30 psi). After I disconnect the gauge and let it stand for a 2-4 hours or overnight then reconnect your gauges and make sure it held vacuum. If the reading dropped any bit, I know I have a leak. To find and fix a leak, I pressurize the system with dry nitrogen gas and then check all the joints and connections with a mostly dish soap and water (they sell a commercial solution for this too if you would prefer to buy it). If there is a leak, it will bubble - even the slightest bubble should be checked. Once it is fixed, do the vacuum procedure again. If it is holding, then I know I've got a good system that is dry and moisture free. Slowly add the R134a until the correct amount is in the system. Sounds like you know what you are doing...but just wanted to stress the importance of a proper moisture evacuation.

Always install a new dryer and o-rings.

The other issue with converting R12 to R134a is the difference in oils. R12 uses mineral oil while R134a uses PAG. You cannot mix mineral and PAG oils. Since it sounds like you will be cleaning your lines with a specialized detergent a few times, you will likely take care of the issue if it is a R12 system converted over to R134a. Just remember to use the proper amount of PAG (and viscosity, like PAG46) in the system.

FWIW, R134a is being slowly phased out as most manufacturers are now going with R1234yf - a more eco friendly refrigerant.

What I did on my 92 EG was convert it all to 95 spec R134. I got all the engine bay lines from a 95 and put them in my 92. Even then I still scrubbed every line with detergent to remove and particles or oils with trace particles in it.

 

oem o-rings, condensor, dryer, evap, expansion, new fluid in the compressor and new clutch.

 

Should have also noted in my other post that 19092 evap coils and 1994-95 evap coils have different inlet sizes. So if you do a full convert on engine bay lines, you will need to do the evap too.

 

very interesting. I may do that since I'd have to remove the evaporator box anyway to replace it.
I plan to get a bottle of nitrogen and a micron gauge when I have the extra funds. I have the major tools needed though so I can get by for now. I'd love to get the digital gauges that tell you refrigerant temps and all that but they're f-ing expensive. Good tip about the 94 and 95 Civic AC parts. There's a 95 Civic at my local junkyard so I'll see if I can get the piping from it.

 

Someone may have said this already, but it's a good idea to replace the hoses as well.

 

A warning that if you want to add the cabin filter, get the evap for that accommodates it, if you want replacement aftermarket. This is a different p/n than the one for a 94-95 Civic. I've used junkyard ones and cleaned them up as a used unit and all is hunky dory but YMMV, so if you're getting a new aftermarket be sure to get the right one.

 

If you're that concerned with having all 134a stuff then this is the way. Find any line set you can from any 93-95 Civic and clean the crap out of it. Use a new compressor, condenser, evaporator, and drier then put it all together with new o-rings. Pull a vacuum, charge with the right amount of refrigerant, and you're gucci.

It's been years since I did an R12 to R134a conversion but I don't remember there being any issues other than the output being less than impressive. The bad news: It took Honda until 2001 Civics to figure out that the small half-size condensers just weren't that great with less efficient R134a. If it's really hot/dry where you live and you spend a lot of time sitting in traffic, expect to sweat a bit. Moving is fine.

A big thing that will help with this is to make sure to close the gap around the perimeter of the condenser, between it and the fan, with foam strips and/or tape (like the factory did). This will make sure that the condenser fan is pulling all of its air across the condenser fins and not around the sides. I've seen quite a few people skip this and their AC just plain doesn't work when the car is not moving.