Those DIY A/C recharge kits..

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Sep 22, 2004
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Are they any good? I was down in Calais, Maine today and looking around the Walmart there. Ah, the oil selection! Anyway, I happened to notice these DIY A/C recharge kits. Only 20 bucks, and it comes with the little hose too. Bottle included the refrigerant, compressor oil, and other stuff. I notice the A/C on the wagon isn't terribly cold, so I figured maybe I'd give one of those kits a try sometime. the wagon is a 1990, but I'm pretty sure it was converted to run R-134a sometime in 99, according to a receipt I found. It was recharged in 99, and I would assume with R-134a. Enough about that, does anyone have any experience with these kits? If I could get one of these kits for something like $30 Canadian (depending on exhange) and recharge my A/C system, I'd be pretty happy. Just a basic A/C system checkup around here is 45-50 bucks, and a recharge would probably be at least that much. If these kits are any good, I'll make a run down across the border and get one, and maybe pick up some Supertech oil filters while I'm there. One more thing, why don't we see these DIY kits anywhere in Canada?
 
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They are kinda iffy. R134a systems are very picky when it comes to the correct charge. With R12 you had a sight glass and if the charge was off a few ounces it would still work. The proper way to recharge a 134a system is to remove, recycle the old refrigerant, check the orface tube for contaminants, vacuum and then to charge the system using a scale. Since your system is still working but just not as cool as you would like you may be able to recharge it yourself. Don't go overboard! Add small amounts of refrigerant and check the outlet temp after every shot. You will need to wait a few minutes between each little charge for the temp to drop. Once it gets to 44F or less stop! Do not add any more as this is one time where more is not better.
 

55Test

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This kit I was looking at has a gauge to tell you when the system is full. I'm guessing it's like a pressure gauge, has yellow, green and red zones. You just stop before you get to the red zone. It sounds easy enough to do.
 
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I retrofitted my '88 Chevy K2500.. I didn't vacuum it down or anything (it was empty)and used one of those kits. I've got 45F air out of the vents, which is fine, but I'm going to pick up a retrofit cycling switch (cuts off at a lower pressure than the R12 one) and see if I can get it to 40F. the only problem *I* have with my AC is the blower simply doesn't move enough air.. it's a brand new blower too. I've not yet pulled the HVAC ducting apart to check for any blockages. my bro's truck ('93c1500) blows about twice as much air as mine. -Bret
 
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quote:
Originally posted by 55: This kit I was looking at has a gauge to tell you when the system is full. I'm guessing it's like a pressure gauge, has yellow, green and red zones. You just stop before you get to the red zone. It sounds easy enough to do.
That is the low side reading only! It's nearly impossible to properly charge a system w/o a hi side and a low side guage hooked up. There are too many variables such as airflow, out side temp etc. Do NOT trust a low side guage only!
 
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Jun 10, 2002
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I'm guessing this is a vehicle already equipped with 134a... Get a cheap gauge, and find a pressure/temp chart for your vehicle. The FSM will have it and probably be cheap on ebay. 3oz low will make for a noticeable decline in A/C performance on a R134A system. Add a can and you are WAY over, and it does not work at all then... For R12 systems, I really suggest fixing it(and fixing it RIGHT) and refilling with R12. It's gotten back into the DIY arena again, as shops don't deal with it much anymore, ones that do want your next child..., and it's easily availble on ebay, with a 609 cert, which you can get from epatest.com for $20. Open book online test... Gauges are cheap as well. R12 systems switched to 134A, even properly converted, tend to fail within a couple of years. With few exceptions, 134A conversions do not blow as cold as they did with R12. Maybe no big deal up north, but no fun here in Texas...
 
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filling your ac systems with one of those kits is like filling your tires with air until the look "full", you really don't know how much of a charge is in the system. too much or too little and it won't function properly. that guage on the can is the equivelent of kicking the tires to see if they are full yet. that kit will work ok, but there is a reason there are special training, licenses, and equipment for doing AC work.
 
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quote:
Originally posted by VaderSS: R12 systems switched to 134A, even properly converted, tend to fail within a couple of years. With few exceptions, 134A conversions do not blow as cold as they did with R12. Maybe no big deal up north, but no fun here in Texas...
i have converted numerous vehicles in Houston, San Antonio and Dallas; a couple of Toyotas, a Chevy, a Buick, a Honda and a Ford and the difference is extremely minor. Most automotive AC have more capacity than even a home unit (on the order of several equivalent tons of AC) and a slight drop in capacity is not even notieable. My 91 camry cranked out low 30s on both types. Usually the drop in perceptible cooling is due to improper conversion/filling which can happen with either type. The correct way involves a vacuum pump and double or triple evacuation to get not only the old stuff out, but the moisture which is the #1 killer of capacity. And of all the ones I've converted, none have even had more than the occassional leak at fittings, which most of them had before the conversion. (several were cars where the value of the r12 was more than the value of the car....) There are a few (very few) older cars with incompatible o-rings supposedly but I've only heard this and have never had anyone tell me exactly what cars this involved. I'm leaning towards urban legend on this one.... Even a beater in Houston needs working AC....and r134a works just fine.
 
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I did quite a few conversions myself, before I got my cert. I did them correctly, flushing and vacing as you mention, and filled them to the correct level, usually 80-90% of the capacity of the R12. In every case, with, the exception of a Dodge Dynasty, the air was warmer after the conversion. The Dodge had the correct condenser for R134a though. The thing I found was that the older the car, the worse the conversion did, and unless a new compressor was put in at the time of conversion, 2 years was the max the compressor would go, after the conversion. Yes, automobile A/C systems are of much higher capacity than most people realize. Switching to 134 reduces output in most cases though. Is it better than no A/C? Yes, quite a bit. Is it as good as it can be? Not in most cases. With R12 still readilly available, I see no point in switching over, provided the job is done correctly. For non DIYers, I understand that the price the few shops that still deal in R12 charge, makes it very attractive to switch. For DIYers though, I see no reason to not use the correct refrigerant.
 
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quote:
Originally posted by VaderSS: The thing I found was that the older the car, the worse the conversion did, and unless a new compressor was put in at the time of conversion, 2 years was the max the compressor would go, after the conversion.
What was the cause of death on the older compressors?
 
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I don't remember the details, but I'd say half died from shaft seal failure, and the rest from internal failure resulting in insuffeicient or no pressure. A few of those were "black death."
 
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