Since I've been so long without A/C in my Legacy, I've really grown to appreciate it, and am willing to do whatever it takes to develop the most efficient and maintenance-free system possible. I've come up with an idea in my head, but it brings up some questions.
I will buy a rebuilt compressor from the same company that is cvaxles.com, don't remember the url though. I'm not sure as to which compressor to get though, because of the modding/retrofitting I want to do.
I was thinking about getting new 94 Legacy pressure lines that are already R134. That way I can just put them on and not have to worry about fittings, which I had a problem with in my first attempt. However, I'm puzzled by a few things. Can I remove the low-pressure line from the condensor relatively easily, or are they one inseparable part? From what I can see, that line is built onto the condensor. The other thing is I'd have to make sure the compressor I get matches those lines. My car originally came with a Calsonic compressor, I don't know what the 94 Legs came with. I know there are also Zexel compressors. Can I just bolt up any compressor I want to, or does fitment change through the years?
Any way anyone can help would be greatly appreciated
"Der Wahnsinn ist nur eine schmale Brücke/die Ufer sind Vernunft und Trieb"
Midnight in a Perfect World on Amazon or order anywhere. The first book in a quartet chronicling the rise of a man from angry criminal to philanthropist. Midnight... is a distopic noirish novel featuring 'Duchess', a modified 1990 Subaru Legacy wagon.
Why are you going to change the compressor to R134 ? You'll pay more for the compressor, fittings won't fit, you'll have the line problems you speak of, and there is precious little chance that the lines for a newer model will fit right. Unless your condenser has a hole in it (not exactly a remote possibility), you should be able to fix your current system for less than $200 on the outside, including a good used compressor and a leak check / charge. Any good yard will guarantee the compressor to work. If your condenser is shot you would have to buy one anyway. There is a good shop here that will charge you $87, then either charge the system with freon, or tell you where the leak is after the pressure test, you go fix it yourself, the come back for another pressure check and the freon at no additional cost. My ex-wife just fixed her Honda AC for a total of $200, including the charge and replacing the rock-holed condenser, with no experience whatsoever.
There's no reason to swap the lines. None whatsoever. If you want....just flush them with ac flush. Either way.....yes you can remove the lines from the condensor. if you look in the grill you'll see the spots where the lines connect to the condensor.
Just get the calsonic compressor for your model year/application. Get a new receiver/dryer. Put the appropriate amounts of esther oil in (according to the haynes ac manual) Take it to a shop, have them pull a vacuum on it, make sure it holds, and charge the system to 75-80% of the original charge capacity.
Only thing I'd do if you really want to be anal is replace the o-rings. I found that the generic o-rings I had wouldn't work, so I said screw it.
I have something to say about this but I have to go to work. If I haven't posted to this thread in the next 24 hours to ring in on the topic, someone PM me.
"Just reading vrg3's convoluted, information-packed posts made me feel better all over again." -- subyluvr2212
The hoses bolt onto the condenser, as Josh describes. They actually attach to the condenser the same way they attach to the compressor. You do need to unbolt the radiator mounts and the condenser itself to allow enough movement to actually remove them, though.
R-12 hoses are different from R-134a hoses. R-134a molecules are smaller than (and so leak more easily than) R-12 molecules, so R-134a systems are designed with barrier hoses that allow less leakage through the hose walls. However, there's more to it. Non-barrier R-12 hoses when used in a functioning R-12 air conditioning system slowly develop a sealing layer on their inside walls from exposure to the mineral oil that is used with R-12 refrigerant. This layer seals adequately to contain R-134a.
What that means, then, is that you can use either R-134a-specific hoses or well-used R-12 hoses with an R-134a system.
Some R-12 A/C compressors cannot be reasonably used in R-134a systems. R-12 is a better refrigerant, so marginal R-12 compressors will do poorly in R-134a service. Also, some R-12 compressors are impossible to completely drain of oil, so they can't be easily converted to the different oil.
Neither of the above really applies to the Calsonic or Zexel compressors used on 90-93 BC/BFs though... they're pretty strong and you can get the oil out.
94 BC/BFs use Zexel compressors. Externally, the compressor looks very similar to the 90-93 Zexel compressor. It's just a little stronger inside, I guess. I actually have one of these that I'm gonna post for sale soon.
I think I remember mile hi saying that mounting was different between Zexel and Calsonic compressors. I know from experience that 90-91 Calsonic compressors mount exactly the same way as 92-93 Calsonic compressors even though the part numbers are different, but I don't know for sure about the Zexels.
But I don't think you should switch compressors. The whole A/C system is just that -- a system. The expansion valve, condenser, evaporator, and compressor are all supposed to work together. You might get unpredictable results. I could be wrong about this, of course, but I think it's probably better to keep the system dynamics close to what the engineers had in mind.
What happened in your first attempt to repair your air conditioning system?
There are a couple things you can do during a retrofit to maximize reliability.
1) Do a thorough flush. You can actually do with aerosol brake cleaner. Fit a rubber stopper onto the end of the little straw, and stick the stopper into whatever you're flushing. Spray until it shoots out the other end. Then blast through it with compressed air, again using some kind of rubber stopper thing to ensure the air goes through the part.
Flush components separately as much as possible, and flush in both directions. When I did it, I separately flushed the discharge hose, the condenser, the condenser-to-receiver-drier line, and then flushed the remainder of the system (the receiver-drier-to-evaporator line, the evaporator, the expansion valve, and the suction hose) all as one unit.
This will get out all the old oil and also let you see if any components shouldn't be reused (lots of black metallic gunk coming out is a sign of that).
Some people say mineral spirits works well as a flush, but I'd be worried that it would wash away the stuff that makes the R-12 hoses usable for R-134a.
2) Replace all the o-rings. You might be tempted to reuse o-rings, and can probably get away with it, but you might as well use new ones while you have the thing apart. Lube the o-rings with compressor oil before installation.
I'll confess that I didn't do this... but I won't mind reservicing my A/C system if I have to. It's pretty easy.
3) Use PAG oil. For your system, I believe you want a viscosity of 100 and approximately 8 fluid ounces. Ester oil is often used for retrofits because it doesn't react as badly with remnants of R-12 and mineral oil, but you did a thorough flush so that shouldn't be a problem. PAG oil is what Subaru specifies even in retrofits, and lubricates the compressor better than ester oil.
Also, pour the oil directly in, rather than using one of those "oil charge" cans. In my experience it's hard to make sure all the oil in an oil charge actually makes it into the system.
I used ester oil anyway, since it's what I had on hand. I did check that it was ISO 100 viscosity.
4) Definitely replace the receiver-drier. Keep the new unit capped until you're about to install it, and only install it when you're about to evacuate the system.
5) Evacuate the system for a long time before recharging it, and use a good vacuum pump. You want to be absolutely certain that there isn't any moisture left in the system. The vacuum allows the moisture to boil out. I used two medium-size refrigerator compressors in series as a vacuum pump, and it actually worked pretty well. I think I got about 28.5 inHg of vacuum at about sea level. To help the moisture boil away, I ran the engine while evacuating, and kept the hood closed (propped up just enough to not squeeze the hoses). The higher temperature helps.
6) When time to add the refrigerant, don't forget to purge the hose with refrigerant before actually charging. Otherwise the small amount of air that's in the hose will slightly contaminate the refrigerant charge.
The original capacity for R-12 Calsonic systems is somewhere between 29 and 32 ounces by weight, so using the 75-80% rule you'd come up with something between 21.75 and 25.60 ounces of R-134a; I used about 22 ounces. The lower charge biases the system to perform better at lower engine speeds, which I think is usually better for most people.
7) Consider not retrofitting. R-12 has actually gotten fairly cheap lately. Depending on how much you buy at a time, the price can be as low as $20 for a charge! If you just buy enough for a single charge, it can still be as cheap as $50. Look on eBay.
R-12 is more efficient than R-134a, so you'll get colder air. It's easier on the compressor, so the compressor will last longer and will load the engine less. It carries mineral oil, which is very reliable and won't react badly with any of the stuff that's potentially gonna be in the system. It doesn't leak as easily. It's what your system was designed to use.
Certification from MACS is fairly easy to get if you want to buy it yourself, or you can try to convince someone at a local shop to buy a bunch of it.
"Just reading vrg3's convoluted, information-packed posts made me feel better all over again." -- subyluvr2212
I did everything pretty much right the first time. I pulled the compressor, drained all the old oil out, put new esther oil in it, and bolted it back up. I replaced the drier, and poured 1oz of esther oil in it too. Then I put the R134 fittings on. Now I didn't flush anything, and I didn't replace any O-rings. I planned on having my dealer pull a vacuum on it not 2 weeks later, but they told me at the last minute they don't do retrofits, coz they don't wanna contaminate the pump with R12.
This was October, so I really wasn't dying for A/C. So I left it completely alone up until late May. Needless to say, that period of disuse caused some problems. I had a friend's shop try pulling a vacuum, and these problems arose: 1) The O-ring going into the drier from the condensor was hissing it was leaking so bad. 2) The low pressure line was reading about 80psi, so they told me that there must be a blockage in it... and 3) at their recommendation, they told me to go to a local a/c shop who gives out free diagnostics. When I took it there, the clutch would not engage at all. I don't think it will at all anymore.
So that's the real reason why I want a new compressor and new lines. Plus the thought of having what would basically be a brand-new real R134 system appeals to me.
Steve, if you wanna send me that compressor real cheap, I can just try mounting it to verify whether or not it'll work, then it could help me if there's a core charge when buying a new one.
I might do all this anyway, if just for the experience and to educate myself more on it. All in due time though, I need the rest of the car operating properly before I fiddle with the A/C.
And my grandparents say I don't prioritize
"Der Wahnsinn ist nur eine schmale Brücke/die Ufer sind Vernunft und Trieb"
I can tell you for sure that leaving a receiver-drier exposed to moisture-laden air for 7 months, especially with a leaky seal, will leave a drier pretty much worthless...
That's weird that the o-ring would have such a bad leak, though... did you inspect it closely when you assembled the system?
There's a pressure switch threaded into the receiver-drier, and among other things it prevents the compressor clutch from engaging when refrigerant charge is low. It protects the compressor, since no refrigerant means no way to return oil. That's probably why your clutch wouldn't engage at the A/C shop.
You only put 1 ounce of oil the drier? I put half the oil in the compressor and half in the drier. While putting it in the compressor I turned the clutch by hand to make sure the oil got through instead of hydrolocking the compressor.
You can do some simple tests of your clutch and compressor:
Test the clutch by jumpering the clutch wire to +12v. Do this with the engine off. Then, turn the crank with a wrench and see if the compressor turns with it.
Test the compressor by disconnecting the lines. Turn the clutch by hand (be sure to turn it in the right direction!) with a finger over the suction port. After just a few turns it should pull a nice vacuum against your fingertip, and when you pull your finger off you should hear air get sucked in. Do the same on the discharge port and you should feel pressure build under your finger and hear it get released to atmosphere when you remove your finger.
If your compressor checks out, you could fix this whole thing pretty cheap. Get a new receiver-drier and o-ring (or maybe just see if your current o-ring is just improperly seated), do the brake-cleaner flush (if you want to), install the drier, and evacuate/charge. Charge it with the Interdynamics R-134a-with-o-ring-conditioner stuff if you like. If you can't do it yourself (or have a friend do it) you'll have to pay a shop to evacuate and charge it, but it might cost about the same amount to build a vacuum pump and get a set of manifold gauges (I have an extra set I'd sell cheap ). Or you could do it ghetto-style without gauges and just use some cleverly set up hose and fittings.
Then you can save up the money for the all new system but in the meantime your car will be a lot more fun to drive for the cost of a tank or two of fuel.
"Just reading vrg3's convoluted, information-packed posts made me feel better all over again." -- subyluvr2212
Hmm... I seem to remember reading somewhere that some Subaru systems use a lighter-than-usual refrigerant oil. But this End Wrench article seems to suggest that our cars all use a viscosity of 100:
Since we're on the topic of AC, I thought I'd pose a question. I was thinking it would be nice if I could pipe my cold air into my intake or maybe just blow cold air on my TMIC. Which would be better or are both bad ideas?
I don't think it would be as effective as plumbing it into an AWIC system to cool the water as the Ford Lightning. You won't make more power on the colder air in the intake as it would take to run the compressor I don't think either.
Steve
Midnight in a Perfect World on Amazon or order anywhere. The first book in a quartet chronicling the rise of a man from angry criminal to philanthropist. Midnight... is a distopic noirish novel featuring 'Duchess', a modified 1990 Subaru Legacy wagon.
You think it would FAR outweigh the gains? I don't know about that. I've noticed electrical draw from my compressor but removing it hasn't made all that much difference in power gains that I can tell.
scottzg wrote:The compressor is an on demand thing- it only works part of the time the ac is on, except if your cooling your charge it would be all the time.
Eh, figure out if its worth it youself-- it takes 6hp to run.
I see, well it's probably not worth the pita of hooking it up.
Josh - Cool, what kind did you end up buying? I stand by my two-fridge-compressor pump.
I think it could be useful to use the A/C system to cool the intercooler (or the intercooler's water) while off-boost. Cuz then when you go on boost you'll benefit from a colder-than-ambient intercooler for at least a few seconds. I guess that's how Ford's system works... parasitic draw when you have power to spare, which gives you more power when you need it.
"Just reading vrg3's convoluted, information-packed posts made me feel better all over again." -- subyluvr2212
will do. I'm not sure when I'm going to do the legacy. The compressor is knocking, I've got a spare, so I may just run it until it craps, or until I get the engine swapped.
I'll probably work on the truck in the upcoming weeks though.
I recharged the a/c system on the nissan yesterday. I got to use the vacuum pump. It worked pretty good. I had issues at first with the hose connections on the gauge set not seating all the way, so it wasn't pulling deep vacuum. Fixed that, pulled a vacuum for 30-45 minutes. Recharged it, and everything's working great. Pressures are where they need to be, and I actually have A/C ALL time, rather then it cutting in and out due to the pressures getting too high.
). Or you could do it ghetto-style without gauges and just use some cleverly set up hose and fittings.