AC wet itself for me too?

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Mar 27, 2012
Pasadena, Ca
I am wondering if something similar, but slightly different happened to me yesterday. Here is a thread I found using the search on AC failure. For reference, I just bought this '82 FJ60 two months ago.

The super short is that my A/C isnt working and the sight on the drier shows absolutely nothing when the car/AC is on or off.

The long story is that I heard a hiss sound on the highway and smelled something burning, I thought rubber, but who knows. When I pulled off at the next exit I could not see anything, but under my hood smelled a bit off. I was almost home so I went home and waited for things to cool down. I checked the coolant to make sure that I didnt loose a radiator hose. coolant is still full, and I have run the car for another 20 minutes and it shows no signs of overheating at all.

But, on my short drive to work today I realized that the A/C is no longer cold. Until that day on the highway, the AC has been amazingly cold. Not anymore. I checked the drier and saw the bolt on the side and it looks in tact. And no sign of bubbles or liquid or foam inside the sight. Was the sound I heard the AC releasing all its pressure? Anywhere else I should check for failure like that? If that is what happened, it wasnt a slow leak.

Any ideas? Thanks. I am hoping its just something to do with the A/C and that the mystery sound and smell isnt something more serious.
more then likely something gave, usually its a slow leak but I bet it went all at once. you can hook gauges up and pressurize with nitrogen, (if you have to you can use a pump but make sure you vac it down real good) and in your case will probably here the leak. If its fixable you can buy freeze 12 and use that. r12 is harder to get.
sounds like you lost all the refrigerant. do NOT charge the system with nitrogen, the water vapor damage you will cause will take $$$ and time to fix. do this: look for a "wet" area where the refrigerant leaked out. the mineral oil is dissolved by the r12 and circulates thru the system - and when it escapes fast, the oil goes with the r12. the system can leak anywhere - even in the evaporator - but start your inspection under the hood. there will be a thin and thick hose/pipe that carries your refrigerant in a circle from the compressor -> condensor -> accumulator -> evaporator -> compressor...trace these hoses and observe. if you find a place that looks "wet" and feels oily you have found where the o-ring or something has failed and let your gas escape.

there is a low-pressure switch on the compressor. when enough refrigerant escapes the system, the compressor will NOT come on; this prevents the compressor from turning with no oil and locking/burning up. (the refrigerant circulates the oil in the system continually and keeps the compressor lubed).

You or someone will need to locate the source of the leak. fix/replace the reason for the leak. pull a full vacuum on the system. charge with refrigerant. AND IF you truly had a fast leak, some/all of the oil must also be replaced.

Your pre-1994 rig was originally using R12 - and if it was never converted, it still is. find a club member to help you or go to a cooling shop. you can NOT fix this without some tools and knowledge.

(that being said - you CAN learn how to do your own refrigeration work and save a bundle. this might be the time to start.)
do NOT charge the system with nitrogen, the water vapor damage you will cause will take $$$ and time to fix.

:confused: In the A/C field that is what is used. You do not want to use air but instead nitrogen. Never heard of this being sold as anything but dry nitrogen.
Thank you all for your replies. I have not found the mineral oil anywhere as evidence for a leak, but I have only looked under the hood. Does this mean I should open the dash next and look at the evaporator? The sound did seem close, as I heard it while driving on the highway.
I did find the high/low fill ports on the compressor. Each is like a bike tire fill where you can push the center pin in to help gas escape. I did this and heard only a weak hiss for a couple seconds and then nothing. So I am assuming it is empty and that I am barking up the right tree.
The dry nitrogen idea does sound good to me. It will not cause any water damage. I have access to pumps and nirogen, so I guess I need to just buy the gauge set for diagnosing and filling. That is, unless I can find the leak by finding the oil.
Oh, I have read through the repair manual and see how to charge and it seems fairly straight forward, except, how do I check and fill the oil in the compressor?

Thank you all.
I decided to try to hunt this down on my own, but have not had success yet, any ideas would be appreciated.
In reading a ton of posts, and thinking of where my problem might be, I decided to switch over to R134a and see if this gives me more options for hunting for the leak. I have only switched fittings, blew out as much oil as I could, and put new oil in. Old drier is still in place until I find the leak, then I will do a more thorough switch over.

I bought the gauge set, a UV flashlight setup, and a can of R134a with the dye in it. Here is what I have found.
If I fill in the low side, and wait, I see a slow decrease of pressure of about 1psi every couple minutes...something like that. If I turn the car on and turn the AC on, the clutch spins, and the pressure gets drained very quickly from the low side and I never have any pressure accumulate on the high side.
I have looked eveywhere that I can for the dye and dont see any evidence for the leak! The one thing that I havent done is look at the evaporator underneath the glove box.

It must be a large leak somewhere along the high side right? Any further suggestions?
I second the use of nitrogen to dry out the lines. It is what we use for this exact purpose. 134A is very sensitive to moisture in the system, R12 not so much. And I believe that R12 doesn't need the higher pressures that 134A does. Good thing I have a supply of the R12, and no I cannot sell any.

:confused: In the A/C field that is what is used. You do not want to use air but instead nitrogen. Never heard of this being sold as anything but dry nitrogen.
dudeman, if you can hear the hissing it is a fast leak. btw, breathing refrigerant can stop a beating heart - so, be sure to leave your windows down if you suspect the evaporator. a leak on the condensor or evaporator would not be as easily detected (without a sniffer) as hearing the hiss. also, you should be able to see something with the UV light/ sure to check when its dark for easier viewing. your patience will pay off. (common atmosphere may also be referred to as nitrogen (78% of what you breathe) and so some people will refer to compressed atmosphere as nitrogen. the pure gas nitrogen would be found in certain automotive/tire shops; compressed atmosphere at scuba shops and paintball fields.)
does the compressor engage when turned on? IF the system is working properly and you are looking at the sight glass (R-12) upon first turn on of the compressor with the engine running you should see some small amoutn of bubbles...then shortly it should clear and then just show clear liquid and or no bubbles.

If the compressor does not engage that is a good clue that you are low or out of freon.

It sound as it maybe a A/c hose blew or maybe teh pressue saftey valve on the compressor.....anyway it soulds as if you have a freon leak. Dont' do anything regarding putting stuff in teh system until you find out where the leak is.

Physical inspection.... most shops will then add a small amount of freon plus an addidive that shows up with a black light to check for leaks. Carry it to an ac shop and I would keep using R-12 if you can still get it where you live as that's the "cold" stuff.. You will not be able to fix teh system yourself unless you have a a/c vaccum pump, proper gauges and a source of freon. You might also have an issue with the compressor itself.
Dave, Elbert, thank you for your comments.
I work in a lab and can borrow and use vac pumps and compressed pure nitrogen. So I bought the 134a gauge set, adapter fittings, and a small can of 134a with dye and the light/ glasses.
But with all of this, I still do not see the leak. I do not hear it either except while doing small charges. I do think I heard it during the catastrophic failure that once, but not since.
The system is and was definitely empty after that big event. Since then, the clutch will engage when filling from the low side with partial dye/freon fills.
But I still have not removed and inspected the evap for the uv dye. I'm guessing that should be my weekend project.
Elbert, you mention a pressure relief on th compressor? I haven't seen this, but there is no leak on the fuse bolt on the drier.
I may be wrong on the valve as my stock AC compressor is long gone...but most ac systems have a high pressure "safety valve" that will blow if pressue reaches to high. As I recall on the GM compressors this was either on the compressor (head) or on the high side of the system. Look through the shop manual to the OEM toyota may or may not have this. I was just thinking off the top of my head.

You will have to pull a vaccum on the system for an extended period once you solve the leaks (part of general AC service) to remove moisture.

I would not screw with the evaporator core unless you are 100% sure that you have no leaks under the hood. If the compressore engages it would seem to me that you would have sufficient pressure to distribute the dye such that you can look for leaks with the black light.... Removing the evaporator core would be the last step in working this issue and first you should determine what parts are serviceable in teh evap core at present time given that many items are no longer avaliable...

in the old days people also used a "sniffer test device" for freon but the results were not so dependable.

If you heard hissing noise under hood....then most likely the leak is "out there" rather than in teh evap core??

When you hear the leak you are unable to determine location or see evidence? Like AC compressor oil leaking?
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I guess I was unclear in my initial description. The only time I heard the leak was when I was on the highway the first time it went bad. I was driving, it was loud because this truck is loud, and I heard and smelled something bad while driving 60. So I pulled over and inspected. I saw nothing, and got it home. The next day I realized the A/C no longer worked and decided this must be what I heard. Since then, when charging, I never hear anything.

One new piece of information. Taking advice from fj60dave, I checked with the UV flashlight after dark. Again I didnt see anything under the hood. But, If I look at the evaporator area under the glove box, there is a hose tucked high up that I cannot really trace. It is ~1" O.D. and has electrical tape wrapped around it. It seems like there is dye creeping/dripping through the electrical tape. Not a ton, but it is there for sure.

Maybe I should remove the evaporator to get room to remove this hose. It must be the one that comes through the firewall. At this point I should be able to unwrap the electrical tape and just pressure check this hose alone. Or maybe it just has something that glows on it because of the tape adhesive? That is my only idea. Next would be to open the evaporator and shine the light on its internal parts.

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