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air conditioning help

you've got 300# of discharge pressure, and no head in the condenser (or not enough to bring the fan on)?? Something isn't adding up there, unless the ambient temp is like -30F :laugh3:
 
This thread is LONG, maybe I missed it, but I don't think anyone pointed out.

The way to diagnosis any AC problem is too put hi & low gauges on the system, with the correct pressure/temp tables, that will tell you if its overcharged/undercharged or malfunctioning, etc.

Without that info, its anyones guess. Your symptoms sound like your low on charge, and that is common, usually a slow leak over years. The AC system is under constant hi-pressure, even when its just sitting and not being used, so its common for it too leak down slightly over the years.

I've added a can of R-134a to my Neon 2 years ago, and tightened up all the fittings, my AC is still working fine. I also checked it with gauges and confirmed that I was low on refrigerant.

Converting from R12 to R134a:
1st-Consider the costs, topping off your system with R12 from a Professional may sound expensive, but its still often cheaper than converting your system to R-134a. Especially if you suspect a slow leak that takes years to leak down to the point it hurts performance, you'll get several years of good performance out of the existing AC.
2nd-Do your research, there are websites about retrofitting AC, they often list by year/make/model what vehicles are good canidates and what vehicles are bad canidates for retrofit. Remember, all things being equal, R12 performs better than R-134a, but they have different properties that require tailoring the AC system for the specific refrigerant. The Refrigerant that the AC system was designed for will always perform best in that system.

R-134a has a lower evaporation pressure, but also a lower condensation temp (or higher pressure). So R-134a systems don't need as big an evaporator as an R12 system, but they do need a much bigger condenser than R12. Trucks and SUV's often are good canidates for retrofit, because they often come with a very big condenser.
 
I have all the new hoses for my system, I was considering coverting to R134A but I'm gona stick with the R12 so is there anyway to transfer R12 from a working system into my system? The only reason why I ask is because I've got 2 S10's I can take the R12 from...
 
Zoro said:
I have all the new hoses for my system, I was considering coverting to R134A but I'm gona stick with the R12 so is there anyway to transfer R12 from a working system into my system? The only reason why I ask is because I've got 2 S10's I can take the R12 from...
Click to expand...
Wellll, maybe, you'd have to work that out with a professional shop. They have expensive equipment for downloading R12 (thats the only legal way to remove it), most charge for the service and keep the R12 and send it to a recycling facility, do they get money for that, I don't know?

You may be able to talk a professional into downloading R12 from one car and then uploading it into another, for a fee.

Be aware, he may have a bottle of R12 that he does all his downloading too, and is probably filled with old R12 from all sorts of old junk vehicles, so if he does this for you, he might be uploading your R12 mixed with rotten old contanminated R12 from a bunch of other junkers, he'll probably warn you of that, if thats the case.

There are ways of improvising to do this yourself, not sure its legal, EPA regs are so screwey they can be interpretted many many ways, the way the EPA interprets them is completly contradictary and makes no sense what so ever.

But improvising it yourself, unless you've got lots of time on your hands, several old refrigerators and propane bottle you were going to throw out, as well as spending a good bit on special fittings, etc. IT would just be easier to try to work it out with a professional.
 
you've got 300# of discharge pressure, and no head in the condenser (or not enough to bring the fan on)?? Something isn't adding up there, unless the ambient temp is like -30F :laugh3:

No, The Aux fan will only turn on when the head pressure is above ~280 AND the engine temp is above ~210. So when you are sitting at a traffic light the system does not kick the aux fan on until the engine begins to feel the effects of lower airflow, which is a few cycles of the thermostat.

The fact that it was not cooling enough was caused by a low coolant level which occured because of the leaky schrader valve. I had checked the pressure with a double gauge, how else do you think I knew the high side pressure?
 
use of R12 is illegal, just to make sure that's clear. also, all A/C systems leak, and they're designed to do it. the question is how much? by the way, they leak at the shaft seal on the compressor, it's considered a controlled leak because the refrigerant has the lube in it that conditions the seal and shaft. when converting R12 to R134a, you should replace all soft lines because (typically) the R12 lines are porus enough that they don't contain the smaller R134a molecules. you also need fitting adapters for the charging ports. R12 is more efficent than R134a, so a retrofitted system will never be 'good as new.'
 
dfreeman616 said:
use of R12 is illegal, just to make sure that's clear.
Click to expand...
Huh? When did that happen? Use of R12 is still legal in R12 systems, but the work must be performed by a licensed technition. The production or importation of R-12 is ILLEGAL, but the use of the remaining stockpile, including recycled R-12 is still legal as long as you follow the EPA rules. You can get a license yourself online, if you graduated high school and got better than a D in science, you can get a license to work on AC with an hour or two of study online.

dfreeman616 said:
also, all A/C systems leak, and they're designed to do it. the question is how much? by the way, they leak at the shaft seal on the compressor, it's considered a controlled leak because the refrigerant has the lube in it that conditions the seal and shaft.
Click to expand...
Huh? Who would design an A/C system to leak? What you say about the shaft seal makes sense, but you don't have leak refrigerant past the seal to get oil to it. I have had AC systems still have a full charge after 10 years and 175k miles of operation, I don't see how you can design a system to leak but only lose a small fraction of an ounce over a decade at 50-250 PSI of constant pressure the entire time. The shaft seal is one of the most common places for a leak to develop. I'm sure even the best working systems have a little bit pass that seal, I don't know if that is design or just the nature, you can't seal anything perfectly forever.

We probably both agree, that often you may have such a slow leak its not worth trying to repair it before servicing the system, you'd probably leak more refrigerant trying to find it and repair it. To meet the EPA reg of attempting to repair the leak before servicing, can be to merely add some die to the refrigerant to find the leak later or what I have done, just tighten up all the fittings and service it. It worked for me, going on 3 years since servicing and still performing fine, so I at least slowed the leak to the point that its almost no leak at all.
dfreeman616 said:
when converting R12 to R134a, you should replace all soft lines because (typically) the R12 lines are porus enough that they don't contain the smaller R134a molecules. you also need fitting adapters for the charging ports. R12 is more efficent than R134a, so a retrofitted system will never be 'good as new.'
Click to expand...
Yes and No, that is where the research comes in that I talked about. Some vehicles with R12 lines already had the special lined hoses to improve AC reliability, and they can handle R134a very well, also they've found in practice it was different than theory, the years of operating R12 impregnated the hoses with regrigerant, that prevent leaking of R-134a when retrofitted, basically the larger R-12 molecues plugged the porous holes and R-134a can't get by. But it is correct in many cases, the R12 line is not able to hold the R-134a because the smaller molecue with diffuse thru the molecular structure of the hose.

I've seen websites with tables for year/make/model of vehicles with notes about retrofitting. Pointing out the potential results, recomending against it or for it, and explaining the measures necessary for that particular vehicle, like the OEM R12 hoses are already teflon or PCV?(not sure if thats the actual lining) lined and will contain R134a or the R12 hoses will contain the R134a OR point out the hoses will NOT contain the R134a and new hoses will be needed.

Yes, R-12 is more efficient than R-134a, but again this is where research comes in. Some vehicles with R12 systems were equipped in such a way (like trucks with huge condensers) that they handle the retro-fit very well and the performance with the R-134a is very very close to original performance of R-12, enough you can't notice the difference. Plenty of other vehicles, are not so well equipped (like the tiny condenser on one side of the grill of the Mini-Van) and they perform horribely on R-134a.
 
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Not sure when Chrysler started installing air conditioning systems charged with 134a instead of R12. But you MUST know what your system is charged with before you re-charge it. You can't mix the two different refrigerants. If your system currently blows "cool" air--cooler than outside temp--then it's possible a can of the appropriate refrigerant will fix your problem; however, if you only get hot air and your compressor does not engage, you have more serious problems and may need to have your system vacuumed and filled by some one who knows what their doing.
 
Re: air conditioning help (OLD post bump)

I'd like to attach to this thread because it's already a nice repository of information on the subject.

Like a lot of people, I decided to try and make my AC work because it's been getting hot out and I guess I don't like my clothing to cling.

Does anyone have any idea on the volume of oil required by our systems? Also, how would you meter this if the oil comes in a pressurized can with a set amount in it? The instructions on the can just say "fill with the desired amount of oil."

I charged my system recently with a propane-based coolant and an adaptor that allows a modern quick-fit hose to attach to the older schrader-lookin' valve on my 1991 Cherokee. The original tag called for 40oz of charge, but this product had an equivilancy on the can. It took me a little less than 3 cans and $60 to get my system up and running.

Apparently, this formulation is frowned upon in the industry because of its flammability and maybe because of its jury-rig nature, but it does let me finally have cold air. I was told by the guy that sold it to me that it is popular in the street rod crowd because it works so well.

There are a couple of cosiderations: Your system must be empty (mine was for some reason), and you must know the volume it takes. I wasn't very sure of was adding the oil, which came in its own can and didn't have any details about how much to add. There was still oil in my lines (a bit came out when removing the valve), so I hope that will keep my compressor alive until I find out if I should charge it with more.
 
The answer is 265GB.

Two windows down, 65 mph, Gold Bond powder.
 
dfreeman616 said:
use of R12 is illegal, just to make sure that's clear. also, all A/C systems leak, and they're designed to do it. the question is how much? by the way, they leak at the shaft seal on the compressor, it's considered a controlled leak because the refrigerant has the lube in it that conditions the seal and shaft. when converting R12 to R134a, you should replace all soft lines because (typically) the R12 lines are porus enough that they don't contain the smaller R134a molecules. you also need fitting adapters for the charging ports. R12 is more efficent than R134a, so a retrofitted system will never be 'good as new.'
Click to expand...

R12 use is not illegal. It is however illegal for car companies to continue to install it in new cars. Using it in an existing car is still legal, but an expensive proposition. I actually found a 30# tank of R12 while at the Carlisle All Chrysler nationals this year and the guy wanted $350 for the whole thing. I shoulda snatched it up :)

One point I don't think I saw yet is that if you do choose to do a retro fit on your own, when you charge the system after you pull a vacuum on it you should use ester oil when you lubricate it. Ester oil will not form sludge in an R12 system like say, PAG oil would.
 
Thanks for a more helpful reply. It lets me know how little I know about A/C. For some people, restoring A/C functionality is as simple as plugging a bottle in and letting it go. It seems that for most other cases, this job should be handled by a professional (or at least with someone experienced in such things advising).

While I'm not sure what kind of oil I have, it comes as part of a line of retrofit products, so I assume it's compatible.

Part of the instructions on the product I wanted to use say not to charge into a vacuum I believe. My system was just at atmospheric pressue as the entire contents had leaked out through a loose fitting.

Haynes and Chilton put all of the A/C stuff in a seperate manual, so it looks like I need another book.
 
PapaPump said:
Thanks for a more helpful reply. It lets me know how little I know about A/C. For some people, restoring A/C functionality is as simple as plugging a bottle in and letting it go. It seems that for most other cases, this job should be handled by a professional (or at least with someone experienced in such things advising).

While I'm not sure what kind of oil I have, it comes as part of a line of retrofit products, so I assume it's compatible.

Part of the instructions on the product I wanted to use say not to charge into a vacuum I believe. My system was just at atmospheric pressue as the entire contents had leaked out through a loose fitting.

Haynes and Chilton put all of the A/C stuff in a seperate manual, so it looks like I need another book.
Click to expand...

You should try and avoid charging into an atmospheric pressure system, as moisture will get into it and cause many headaches. When you charge into a vacuum, it helps prevent moisture from getting in. A/C in my Chrysler is supposed to be as simple as dumping in that bottle, but last year I had to replace the evap core (WHOLE dash had to come out) and the receiver/dryer. Learned a lot in the process.

I found this thread because I'm looking at getting the A/C in my 96 XJ Country back up and running. Blows hot air right now. I'm gonna put a charge in it with some leak detector and see what comes of it.
 
The only way to remove moisture from a refrigeration/freezer system is to pull a heavy vacuum. The low pressure created by the vacuum causes any moisture in the system to "boil", allowing it to be sucked out.
Any time a leak develops in a system, there is a potential for air to enter. Air is synonymous with moisture. Once you get air in the system, it must be vacuumed to remove it. If you don't remove the air(moisture), the system will not function properly.
If the system has been opened up to replace any component, or has developed a leak resulting in "0" pressure in the system, air has entered. So, along with component replacement, or leak repair, the filter/dryer should also be replaced. This will insure removing the last bit of moisture that vacuuming may miss.
 
xjbubba said:
The only way to remove moisture from a refrigeration/freezer system is to pull a heavy vacuum. The low pressure created by the vacuum causes any moisture in the system to "boil", allowing it to be sucked out.
Any time a leak develops in a system, there is a potential for air to enter. Air is synonymous with moisture. Once you get air in the system, it must be vacuumed to remove it. If you don't remove the air(moisture), the system will not function properly.
If the system has been opened up to replace any component, or has developed a leak resulting in "0" pressure in the system, air has entered. So, along with component replacement, or leak repair, the filter/dryer should also be replaced. This will insure removing the last bit of moisture that vacuuming may miss.
Click to expand...

That could be a little bit of overkill. Depending on how long a system has been "open" it may not need replacing.

Other than that your post is right on.
 
Replacing the filter/dryer is cheap insurance to insure the time and cost of vacuuming, and re-charge was not wasted.
 
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