legacycentral bbs

Well I just finished up the conversion on my 1990 Legacy today to R134a. I must say, the conversion wasn't that hard and the results are good. I know people bitch and moan that converting doesn't work and blah blah blah. If you do it right, it works fine. Procedure should be similar if not same for imprezas too.

I'm goin to give a little tutorial on the basics of what needs to be done to have a successful swap.

The first thing that needs to be done is the system discharged. You can do this the "proper" way by using a vacuum pump, or just loosen one of the bolts a little and let things vent......you shouldn't do this....but I can't stop you

Next you need to get all the old oil out of the system. Most of it will be in the compressor and receiver/dryer. You will need to replace the receiver/dryer anyway, so you can leave that alone right now.

Unfortunately to get the oil out of the A/C compressor, you will need to take it out. Loosen the belts for the alternator & a/c, remove the lines from the compressor, and unbolt the compressor. Once you get it out, dump out the oil from the intake & discharge holes. Turn the compressor clutch a couple times to get any excess oil out. There is also a drain hole on the side of the compressor. It wouldn't be a bad idea to remove that and make sure everything's completely out.

Leave the compressor out for the time being.

Next remove the lines that connect to the receiver dryer, and also remove the pressure sensor. Once you have them disconnected, loosen the bolt that holds the clamp down on the receiver/dryer.

Check all the o-rings and make sure they're good. If they're good, you don't need to replace them. Mine were fine.

Next take some compressed air and blow through the line that goes to the condensor from the compressor. Put a rag under that line at the receiver/dryer to catch any oil or other gunk that comes out.

If you get any nasty black goo, or anything that looks bad, you should probably flush the system with some flush stuff.

At this point, you have the option to take the evaporator box out. You don't need to take it out, however gunk, leaves, etc gather in there and can cause things to stink up pretty bad. Mine was nasty.

Here's some pics of before an after.

Needless to say I took my evap box out. It really wasn't that difficult. You must first remove the lines that connect to the lines in the evap box. Once you do that you will need to take out the glove box, and the plate that it bolts to. There is a bolt at the bottom and nut at the top of the evap box. Remove those two and the whole thing comes right out.

I cleaned everything up with pinesol. It worked very well.

Once you get it clean, put it back in, in reverse order.

Now you're ready to put everything back together.

As I mentioned, you will need a new receiver/dryer. Just get the one for your car at a local autoparts store. I got mine at autozone for 45 bucks.

I guess now is as good as any to talk about other supplies.

Oil. r134a & r12 refrigerants use different oils. The oil acts as a means of transportation for the refrigerant. R12 systems use mineral oil. Most newer 134a systems use PAG oil. PAG oil is a synthetic oil. It however has zero compatibility with mineral oil. So it's not the best choice when doing a conversion.

Esther oil however does work with r134a, and is compatible with mineral oil. So you don't have to get every last drop of mineral oil out. However you should try to get as much as you can out.

So, while you're at the parts store, you will need a receiver/dryer, some esther oil, and some r134a refrigerant.

Note, you probably don't want to get the refrigerant that has oil and other crap in it. As it will probably have incompatible oil in it.

Now let's talk about the amount of oil & r134a you will need.

It will vary for different vehicles, but on mine, it said to put in about 5 oz. of oil. When you put the oil in, you want to put about 1 oz in the receiver dryer, and then put the rest in the suction port on the compressor.

For refrigerant. You want to fill the system to about 75-80% of the original r12 capacity. Mine called for about 1.8-2.0 lbs of R12, so I used 1.5 lbs of R134a.

Last thing you will need is the new R134a fittings.

So....now that you have all your supplies....time to put everything back together.

Like I mentioned, put about 1 oz of the esther oil in the receiver/dryer, and put the lines and the pressure sensor in it. The receiver/dryer should come with new o-rings....you can put those on.

Pour the remaining esther oil that your system calls for in the compressor, like mentioned above. Now the compressor is ready to bolt back in the car. Bolt it back in and connect the high and low pressure side lines. Put all your belts and such back together.

Now put on the new fittings, and you should be ready to pull a vacuum. I took my car to a shop at this point, since I couldn't find a place to rent a vacuum pump and it cost more to buy one then to just take it to a shop.

The hooked the vacuum pump up, sucked all the air out. This also boils all the water out of the system. Once it was all out. They let it sit for 10 min to make sure there was no leaks. He added as much refrigerant as he could with the car off, and then had me start it, and finished adding the appropriate amount of 134a.

That's it. It really wasn't that hard, and she blows nice and cold air. Only issue I have is that since I have an underdrive pulley on, the compressor really isn't spinning fast enough at idle speed. If I get ambitious I may swap it out for a non-underdriven, but lightened pulley. We'll see.

Total cost: $118.97 + tax

Receiver/dryer: $43.99
2 cans of r134a: $12.00
Esther Oil: $6.99
Fittings: $5.99
Labor for vacuum: $50.00

I got a deal on labor for the vacuum and charge....that may be a little more, depending on the shop you go to.

Not bad for $120.00, and it won't cost an arm and leg to recharge.

Also, forgot to mention I had the aid of a buddy who told me most of what I just told you. Plus he recommended the Haynes Heating & Air conditioning tech book. I think it was like $15. It has all the oil amounts & refrige amounts too.

Very helpful, and would highly recommend you get one if you are planning on do a/c work yourself

Here's the link to the haynes tech manuals

Here's the book number and info

10425 - Automotive Heating & Air Conditioning, Covers theory and operation of all heating and air conditioning systems in use today. Step-by-step procedures are provided for diagnosis, maintenance and repair.


Edit: Just thought I'd update this thread with some additional details. I would recommend using PAG oil over esther oil. I believe I had several compressor failures possibly due to the esther oil not providing as good of lubrication. The downside is you'll need to try and clean/flush out as much of the old mineral oil as you can. It's a good idea to dump out the old oil in the compressor into a measuring cup to see how much oil is in the compressor and depending on how much you get out of the compressor, adjust the total amount of PAG oil you fill the system with. Our compressors use PAG 100.

nice info since i'll probably have to do this..

What are the "fittings" you'r talking about ? detail ? where do you bought them ?

thanx !

The fittings are simply the fittings that screw onto the existing r12 service ports that allow you to use the fittings and associated stuff for r134a refrigerant servicing, etc.

You should be able to find them at your local parts store.

Thanks for posting this information, Josh! Clear step-by-step instructions are awesome.

If the old refrigerant discharges on its own when you open the lines, why do you need a vacuum pump? Don't you just need a receptacle to catch the old refrigerant?

What type of compressed air did you use to blow out the line between the compressor and condensor? Just a shop air compressor (like the kind you use for air tools)?

Thanks for the tip on the Esther oil. The factory Subaru retrofit kits come with PAG oil. Couldn't you just add the oil after the shop pulls the vacuum on the whole system? That ought to get all the old oil out, no?

Do you have the Zexel or Calsonic A/C system? I need to do this exact same procedure with my Calsonic.

I may need to replace my compressor, too, though; it's been knocking. Anyone know a good source for a new Calsonic compressor that won't cost me $400?

vrg3,

The old refrig does vent when you open the lines....also...when you do this...make sure you're in a good vented area and put a rag around the fitting your opening up. Also, do it a little at a time. I opened up the high pressure line at the compressor. I put a paper towel around it, so oil wouldn't go spurting everywhere. However there really wasn't much oil in the system, which was probably the cause of the compressor knocking. I let it vent for a little bit, when it slowed, I opened a little more until everything stopped hissing.

The reason you need a vacuum pump is because when you open up the system, moisture can get in there and moisture in the a/c system is quite bad. There's some other reasons I think, but I'm not exactly sure without researching the theory behind how a/c systems work. Just take my word, you need to have a vacuum pulled on the system before a charge is put on it. This also will tell you if you have any major leaks if the system doesn't hold a vacuum.

I actually used a stupid little duster can.....but yeah....just use air from a compressor. I am severely limited on my shop space and resources......it's getting to a boiling point with me. Not having the space nor an air compressor and the proper tools to do the work I need to do. I will be living in a place with a garage before the summer is out.....that I can promise you.......

You really need to have oil in the system....or should.....since you have it all broken down. Again....I don't know the theory behind why you need to do this. All I know is that you need to have oil in there, and that the two main places it will usually collect is in the compressor and receiver/dryer. Even the tech who pulled the vacuum and charged it asked how much oil I put in, and where I put it. He acknowledged what I did, 1 oz in r/d & remaining in the compressor was fine.

Pulling a vacuum on a sealed system will not get the oil out. The oil can exist in a vacuum without boiling off. If you had an open system....ie. one end open to atmosphere, and a high enough volume pump, you could in theory suck all the oil out.....however I don't think that would work too well.

I have the calsonic a/c system.

What year t-legacy do you have again? If you give me the info, I can give you the exact specs on how much oil and how much refrige you will need.

Also, you may want to check junkyard for a used compressor. Any of the compressors for the calsonic systems should work. There were some variations between years, so make sure you know what year car you pulled the compressor from, because that can determine how much oil you need to put in.

looks like I'll be doing this again real soon. My compressor shit the bed this morning. The rpms went all freaky.....then I noticed a pretty nasty smell...along with warm air. I turned the a/c off to see if the smell was still coming in.

When I got home I could hear the compressor making rattling noises...even with it not engaged. The paint on the clutch actually bubbled it apparently got that hot!!!

So vrg3 hopefully that compressor I got from you is good! I may try to replace all the o-rings....not sure...depends if I can get them easily or not as a kit, or possibly generic from parts store.

Aw, that sucks... What do you think it was that killed the compressor?

The o-rings that came with my OEM retrofit kit were part number 73039AA010... It came with four of them loose. I don't know if any came packaged with the receiver/dryer, as I still have not gotten around to repairing my air conditioning system.

You might consider trying to use PAG oil this time around. It's supposed to lubricate better than ester oil, and R-134a carries it better than ester oil.

Also, I remember reading somewhere that Subaru A/C systems use a much lighter viscosity of PAG oil than most other cars'. Do you know if you used a light-viscosity ester oil?

Maybe a can of flush and OEM PAG oil would be the way to go this time around...

Really not positive on what killed the compressor. I had tried to get the clutch off this one....so it's possible I boogered something up in the process. It leaked refridge/oil through the shaft seal for a while. So it could've been a number of things. I had sort of expected to have to replace it.

I'm going to disassemble everthing tonight, and take the o-rings to the parts store. The guy said they had a misc selection of ac o-rings as well as a receiver/dryer.

The main reason I don't want to use PAG oil is it's not compatible with mineral oil. So unless you get 100% of mineral oil out of the system, it's probably not the best idea to use. I just used esther oil, I don't think I used any particular kind. I could see if there was a "thicker" esther oil. We'll see.

I don't think it's really true that you have to get 100% of the mineral oil out. It's not compatible with R-134a/PAG in the sense that it won't mix with them, but it's not like it's going to disintegrate the PAG oil or the refrigerant. It'll just occupy space.

That's why I suggest the A/C flush. That's how I'm gonna do it.

Subaru's OEM retrofit kits come with PAG oil and don't even include any flushing agent.

I have a question about this....

I never knew how cold my AC was before it was converted since it never worked prior.

Hearing that because R134a runs at a much higher operating pressure than R12, R12 systems must be charged with less R134a refrigerant. Therefore the system won't be as efficient and as a result wont blow as cold.

I was just wondering how much worse should the AC be after conversion? After sitting in the sun Mine takes a while just to get down to 40 degrees (out of the vent) on max AC and number 4. Much longer than any other normally operating system that I have seen.

It has been like that ever since I had the AC fixed and converted at a somewhat reputable shop.

I'm just wondering, after the conversion, should it be that inefficient? By the time it finally starts to cool the car off, im almost to my next stop.

Andrew

I will tell you that after I converted mine. It blows much colder then even some new cars i've been in.

So honestly....it really depends I think on how the conversion was done.

There's a guy in FL that I talked to about the whole conversion process. He was an ac technician or worked in the bus, and told me everything he did for his car. So I'm pretty inclined to believe what he's got to say. I'll ask him about the pag vs. esther oil and how well it transports the refridgerent.

Ok....started the tear down tonight. I stripped pretty much all the A/C components, minus the condensor in an hour.....I still am really surprised at how easily everything comes apart.

I checked on the esther oil viscosity. It has a viscosity of 100. There are two PAG oils, low visc, which is around 46, and high visc, which is around 150. So I'm goin to stick with esther, as it's suited for both refridgerants, and does have a pretty decent viscosity.

I got a new receiver/dryer, and some flush. I'll flush the lines out tomorrow, and depending on how much I get done, I'll probably try and at least put the compressor and stuff in so the car is driveable. Had to drive the beater to the parts store and will be driving it to work tomorrow...yah.

I'm going to call the guy who worked on my a/c in the house and see if he can tell me where to get some cleaner to clean out the evap. He had some acid stuff.....I'm sick of the damn thing stinking.

Barring no major complications....I should have everything back together by the weekend.....and depending on when I can take it to my buddy's shop to have them pull a vacuum on it......I'll be back in business.

One thing I'm not sure about is the o-rings. The parts store had the same o-ring kit I do, so I didn't bother. Are o-rings, o-rings....or is there a difference for a/c ones? Also....the ones I have are probably a little fatter then the stock ones.....not sure if that will be an issue or not......

Got everything back together last night. I prob won't be able to get it recharged until saturday though.....oh well.

pics
http://www.main.experiencetherave.com:8 ... ges/accomp

well i did mine too the other day i didnt do anything except add the fittings because it said the oil that the kit came with was compatible with the r12 and my uncle said it was fine so it works great really cold air now hehe

Well, I did some research and i'm starting to think that the shop that did my conversion overfilled it with oil. I don't think they overcharged the system, I just think they put too much oil in and not enough refrigerant.

On a 2.5 hour drive on the interstate yesterday, I had the fan speed between 3 and 4 on MAX AC at all times.... The AC system should be most efficient on the interstate since that is when the most air is being forced over the condenser. Yet mine could hardly keep up (granted it is Florida and the temp was in the 90's....but still).... While it was enough to stay comfortable, It doesn't seem normal to have to keep it on 3 or 4 and MAX AC while on the interstate (not to mention how long it takes to cool the car off after being parked in the sun.)

I'm not sure what I want to do about it though... The AC already "works," and i'm not sure if I want to spend the money to take a chance that the previous shop overfilled it with oil (at least my compressor would be happy.) It's also hard to find a reputable shop nowadays.... Maybe thats as good as my system is gonna get with the r134a, but it just doesn't seem normal....

Andrew

Andrew, I think you're expecting too much from your a/c for this reason...



I have never driven a car here that has kept the interior at a perfectly comfortable temperature. At best, it just blows cold air all over you so you're not burning up.

Possibly.... but as Josh said...


And he lives in Texas...


My mom's 99 protege and dad's 03 stratus work great, so I would expect at least something close to that from what Josh said...

Andrew

I never had a problem driving through the desert in summer. Of course, that's a dry heat, but we get stretches of 100+ with high humidity here and my A/C did quite well until the compressor packed it in.

Steve

before I converted mine I had similar issues on the interstate. I had it charged with r12. It worked good around town, however on the interestate it was like the compressor was cycling off too much or something. When i did the conversion I had no problems, either on the interstate or in town. If done right....and I'm going to say mine is done right....the a/c will still blow very cold with r134a

yeah.....I'm in houston.....freaking hot and humid.....it is the ultimate test of an a/c system.

Finally got the system charged up this morning. She still cools like a mofo. Temps got to like 47 or so....with just letting it sit there for a little bit. low pressure side was right around 30 (not sure the units)

I'll see how everything reacts in the next few days....but I still say that when these systems are done right.....they will still freeze your ass.

Well, mine is even worse around town.... and putting it on regular AC during the day... forget about it....

Maybe i could take everything apart, drain it, then have it filled with the proper amounts of everything, and see how it does...

Andrew

I'd recommend doing that Andrew.

It's something you can do yourself. Take it all apart.....dump all the oil you can out of the compressor. Replace the receiver dryer, put the correct amount of oil and refrigerant in.....and you should be good.

Let me know if you want to go that route, and I'll look the specifics for your system.

Well, summer will be here before I know it, and I would like to replace the refrigerant and oil...
Should I flush the lines out with anything?? I don't have access to compressed air. What about pulling a vacuum? I'm certain that there are no leaks in the system...

The specs for my system would be nice josh... Thanks

Andrew

You do need clean compressed air to clean out whatever you use to flush the system. And you do need to use a vacuum pump to evacuate the system before charging it. You can make a vacuum pump pretty cheaply from some old refrigerator compressors.