A/C Problems and Questions - Next Step?

[07Evolved]

Hey everyone,
Since I just moved to AZ, it is imperative that I get my A/C going! I don't really want to be stuck on the freeways out here in traffic without A/C.

So, I have searched and gained more knowledge about our A/C systems, but I still have a few questions...

First off, I need to explain my current situation:

I first put on R-134a adapters to my R12 system on both the high and low sides of the system. The other day, I recharged the system with R134a. It seemed to blow colder air but not cold enough. There didn't seem to be any leaks and the compressor was cycling and the clutch was engaging/disengaging.

So today, again I tried to recharge the system again to make it colder. This time, I bought a recharger system that had a gauge on it. I recharged the system and it went up to about 25-26 psi with the A/C turned on. However, I noticed that the compressor wasn't cycling today but the clutch was turning on and off when I turned the A/C on and off in the car.

So, I don't know what the next step is. Is there a leak? Do I try to get some dye to look into a leak?

Is the compressor bad? I'm sure it is the original compressor. Do I replace it?

I'm just not very knowledgeable with air conditioning so I would greatly appreciate any help and input.

Thank you everyone,
Brad

[ericem]

The o-rings that seal the lines to the compressor most likely leak I know on my car and alot of other Subies it is a common place. They are only a couple cents or so.

If it short cycles very very fast, it could be you overfilled it. How many oz worth of freon did you put? The oz is written on the can, the system holds 23-25oz I believe. So if a bottle is 5oz for ex (i don't know exactly though) put 4 cans see how it runs, then add a bit of one more can and see how it works.

The a/c will cycle on and off btw, but with max a/c on and at level 4 fan on the coldest setting should run pretty steady. Also idea is doing what this while refilling the system.

[07Evolved]

I put in about 24 oz or so because I know it had to be empty. Thank you for the input on the o-rings. I guess I should perform a leak test today. Do you happen to know the part numbers for the o-rings? Thank you very much for the help!

[07Evolved]

Ok, I just went out and checked the pressures again at the low side....it reads about 25-28 psi when the A/C is on and it reads about 55-60 when it is off. Does this help determine anything? I'm on my way to get some dye for a leak test.

[ericem]

hmm my dad does heating and ac he filled up my car not sure what the low pressure side read but i can find out if it drops that much i would assume it is low on refrigerent. i just called my dealer with the vin number and told him i need the orings for the lines attached to the ac compressor.

[07Evolved]

ok, thanks man. i just did a leak test too and nothing seems to be leaking. the guy at the auto parts store told me that if the compressor is bad, it should be making some sort of grinding noise? is that true? i know mine isn't making that noise and it turns on, the clutch engages, but it still doesn't cycle on and off and the clutch stays on. could it be o-rings?

[ericem]

It is hard to tell also remember the gauges that come with the kits suck. Realistically the best thing to do would have been having a automotive place pull a vacuum on the system. You might as well replace the two o-rings since they are cheap. Problem is leaks can occur when the engine is cool so the leak tester may not work. When my dad gets home ill ask him though about the pressures.

Also I doubt the system was empty, did you push on the shradder valves before filling to verify? I have a funny feeling it is overfilled instead of underfilled now. Also did you fill the system via the fat line (low pressure) or the skinnier line coming from the front condenser (high pressure) ? and what are you measuring the pressures use low and high?

[07Evolved]

It is hard to tell also remember the gauges that come with the kits suck. Realistically the best thing to do would have been having a automotive place pull a vacuum on the system. You might as well replace the two o-rings since they are cheap. Problem is leaks can occur when the engine is cool so the leak tester may not work. When my dad gets home ill ask him though about the pressures.

Also I doubt the system was empty, did you push on the shradder valves before filling to verify? I have a funny feeling it is overfilled instead of underfilled now. Also did you fill the system via the fat line (low pressure) or the skinnier line coming from the front condenser (high pressure) ? and what are you measuring the pressures use low and high?

Well I went ahead and replaced the two o-rings at the high and low side going into the compressor and also the o-ring for the coupling going into the firewall. I had the system completely drained because I took off all of the lines and the pressure came out and I verified this by measuring the low side and it was at 0 psi. I did push on the shradder valves and nothing came out. I filled the system with the low side. I haven't measured the high side because I don't have the professional gauges, just the cheap gauge that comes with these refilling kits.

So, I just replaced the 3 o-rings, emptied the system. I turned the A/C on in the car, the compressor came on but the clutch didn't engage. Only until I started recharging the system did the clutch engage once more. I filled the system until it hit 25-28 psi. I didn't see any leaks or anything, the compressor was on and the clutch was engaged but still NO AIR. I don't know what else to do. Could it be just that the compressor is shot and I just need to replace it?

[ericem]

The fans are turning on correct? also how does the front condensor look? make sure it is clear or it will not work!

[ericem]

I talked to my dad he said you must pull a vacuum before you refill the system because there would be air in the system and it will condense and a bunch of other stuff he said including it will damage the compressor. The main thing is you need to get the system vacuumed before refilling with refrigerant and I asked what pressure it was on my car on the low pressure side, he said he would assume it would be even higher then 50psi especially if it's a hot climate.

[07Evolved]

Thank you very much for checking on that. I really do appreciate it.

Yes, the fans are turning on...where is the condensor and how do I see if it is clear?

Ok, so what you are saying is that the compressor probably has moisture in it like what happens over time with an air compressor and that is affecting its output? So, I get all of that out and then recharge it again? Is that it? Can my local auto parts store do that?

Thanks again!!!

[ericem]

The condensor is the rad looking item right infront of the rad.

You can ask a part store if they can pull a vacuum on it.

Better yet, find a private HVAC guy and throw him a few bucks. Just tell him you need someone to pull a vacuum on your car and tell him it came with r12 so his guages will hook up without any adapters. I am sure he could also refill it with r134a he should have a tank in his truck. To bad your not closer haha then again if your here you probably would be ok without a/c

[07Evolved]

Haha, true. I'm sure I wouldn't really bother with A/C if I was that far north.

I will definitely try and find a private HVAC guy, that is a great idea. Thank you for the head's up. Hopefully he won't charge me an arm and a leg. If I get a vacuum pulled on it and get him to refill it, and then it still doesn't work, what then? I'm guessing the HVAC guy might have some input?

Thank you so very much again man! I really appreciate all of the help and please tell your father thank you as well!

[07Evolved]

I just checked the condensor...I'm assuming you mean clear of debris and nothing blocking it right?

[ericem]

Yup should be able to see through it if you have light on the other side.

[07Evolved]

yes sir, i just shined a light at it and the light came through the other side

[07Evolved]

No such luck with the local auto parts store...they don't pull vacuums on a/c systems. I will try with some local hvac companies to see if they might help me out.

[Legacy777]

I'm assuming this is on your 91 Legacy?

I'd really suggest reading over my thread
http://bbs.legacycentral.org/viewtopic.php?f=11&t=1083

The system needs to be stabilized (run for about 10-15 minutes so the oil ends up in the right spot) Then when the system is stabalized, it needs to be depressurized, and the oil in the compressor and receiver/drier drained out into separate measuring cups. R134a compatible oil needs to be put back in its place. Unless you clean everything out, you really need to use esther oil. PAG oil I think is better for the compressors, but does not mix with the mineral based oil. You also need to replace the receiver drier (put the new oil in it.

When all that is done, have a deep vacuum pulled on the system for about 30 minutes. Let it sit for about 5 minutes to make sure there's no leaks, and then recharge the system. I'd recommend using about 75-80% of the original r12 refrigerant amount. These compressors are wobble compressors and can vary the geometry of the compression stroke, and therefore do not cycle like most newer compressors.

Really, I'd recommend taking it to an AC shop. Getting the tools and knowing exactly what to do can be expensive and difficult.

[07Evolved]

I'm assuming this is on your 91 Legacy?

I'd really suggest reading over my thread
http://bbs.legacycentral.org/viewtopic.php?f=11&t=1083

The system needs to be stabilized (run for about 10-15 minutes so the oil ends up in the right spot) Then when the system is stabalized, it needs to be depressurized, and the oil in the compressor and receiver/drier drained out into separate measuring cups. R134a compatible oil needs to be put back in its place. Unless you clean everything out, you really need to use esther oil. PAG oil I think is better for the compressors, but does not mix with the mineral based oil. You also need to replace the receiver drier (put the new oil in it.

When all that is done, have a deep vacuum pulled on the system for about 30 minutes. Let it sit for about 5 minutes to make sure there's no leaks, and then recharge the system. I'd recommend using about 75-80% of the original r12 refrigerant amount. These compressors are wobble compressors and can vary the geometry of the compression stroke, and therefore do not cycle like most newer compressors.

Really, I'd recommend taking it to an AC shop. Getting the tools and knowing exactly what to do can be expensive and difficult.

Yes, it is on my 91 Legacy. Thank you for all of the input and help. I am really starting to agree with your final statement...this is really starting to add up in expenses and I have never messed with A/C systems like this in detail. I am beginning to think I am better off taking it to the professionals so I know it will fixed. I hate to bite that bullet, but it is looking like a line has been drawn like you said to either start buying expensive tools and material myself to get it done or just take it to the professionals.

Thank you again!!

[slipknot51]

From what I have learned from doing A/C on truck which is the same as car's. If you are getting low side pressures of 25-28 Most systems have the low side pressure switches like ours or thermistors/ temp sensors to protect the evaporator from freezing up which doesn't sound bad but it usually causes the compressor clutch to cycle and when its hot its not good to have cycling (its different per system )because over a long period of time the constant freeze up causes the temps out the ducts to increase and not cool well at all. This is usually caused by poor air flow through the evaporator or a undercharged system. I would do what Josh recommends by taking a putting a vacuum on the system for 30 minutes. By doing so you remove the moisture that develops in the system besides whats collected in the receiver/drier. Another thing that is recommend is to have the proper amount of oil in the system the oil helps with of corse lubracation of the compressor it also helps with the Refrigerant flowing through the system to much actually takes away from the amount of refrigerant that can go into the system

[91Beater]

FYI:

Autozone and O'Reilley's suck at important parts. They have plethora of decorative and accessory type crap, but I've found that my local NAPA has much better parts selection when it comes to A/C.

For the compressor connection get a pack of AC O-rings. I paid $7 at NAPA.
I used this filter drier: $15.
http://napaonline.com/Catalog/CatalogIt ... 0363453501

Pull a vacuum for ten minutes or so, then shut off the manifold gauge and the vacuum pump.
Come back to it about an hour later. If the vacuum has dropped, you need to go chase the leak.

It is at one or more of fittings or the front seal on the compressor.

Once you locate and fix the leak, add two cans of 12oz R134a. You may want to use a can with UV dye and oil in it and one plain one. Since our system is rated for 28-30oz and standard practice is 85% of R12 charge, so you'll get a good starting amount. You want about an ounce of oil added to go with the new filter drier.

Go pickup a swirly CFL black light and put it in work light to look for leaks.

The NAPA filter drier comes with a set of O-rings for the connection. Don't install the filter drier until the day you're going to pull the vacuum and charge the system.