ac charging

Old 04-23-08, 06:07 PM
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ac charging

O own a 2000 alero and the ac is not blowing cool at all and the compressor isn't working, the compressor belt is moving but the actual compressor isn't clicking on.
It was getting warm last year and not cooling as much as it used to.
it has never been charged the 8 years i have owned it so i'm thinking it's time for a recharge.
can i buy a home recharge kit from autozone and do it myself.
any special instructions i need to know before i do this?
How do I do I recharge the system correctly for my situation.

how many cans of "freon" do i need etc...
Old 04-24-08, 07:03 AM
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the short answer is yes you can charge it yourself, but you should take it to a shop that can leak check it. If you do it yourself the amount of refigerant depends on system pressure.
your low side is where you add and it should not exceed about 35 psi when charged. place a thermometer in the air vents and keep checking the temp as you add refigerant until you can blow out about 40-50 degree air, the no will be higher if the humidity is high. under no circumstance should you exceed the weight of ref. specified by your decal.
Murphy was an optimist.
Old 04-24-08, 08:35 AM
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1. yes, you can do it yourself
2. yes, it is wise to go for leaktest. if you have extra cash and time on hand. or you will waste all the freon you put in in some time.
3. if you decide to DIY it, you have 2 choices: buy a recharge kit and seperate supplies; buy a can of freon with already attached recharging tube/connector. advantage of 1st - you can use it many times, you save some $$ on supplies; disadvantage - you'll pay for a bunch of pieces you'll never use. advantage of 2nd - it's plug and play; disadvantage - caps are made out of plastic, don't seal too well on AC connector.
4. you can buy seperate freon (134 in your case, as far as i remember) and you must buy a can of AC oil to go along with it. or, you can buy a premixed one, and that's what i do. if you do not put oil in, it'll work dendy for some time, and then compressor will seeze. done that. not end of the world, but then you need to pull compressor off the engine and manually crank it adding oil and such. headache.
5. before getting into all this, might be a good idea to look around and maybe find an AC pressure gauge and check system pressure. if your pressure is up to spec and compressor does not kick in - you either have toast clutch, or something else is not working. otherwise, you'll overcharge the system and it'll never kick in for safety reasons. done that.
6. to recharge the system, you must have compressor running. ergo, it had to be recharged when it was running low on freon, or when it was blowing warmer then normal cold air. then compressor was working.
7. if the system is low on freon/oil, it has pressure switch that will not kick compressor in for safety reasons. usually sits on top of expension canister or in one of the lines, next to the firewall. big round piece, with 2 contacts sticking out and connector. easy to spot. anyways, if system is low on freon, then it is a good possibility you had slow leak and then doing what goodwrench suggested is wise. and it's most likely the case, as well sealed systems run almost forever.
8. under the circumstance that there is not enough pressure in the system to initiate compressor, and you still want to DIY - you have to trick system into believing that pressure is fine. at this point, i'd rather not post how to do it for the whole entire internet to read. it's very doable, though, and i have done it 5 or 6 times, i believe.
9. as a matter of fact, i have just remembered a 2nd, less harmful way. done that either, just memory being slow. you'll need to get to the compressor clutch connector and splice into it. splice in with heavy gauge wires. then get a charged battery, or come up with a way to get juice off bettery with engine running. turn your engine on and run 12 V down to that clutch. point is simply to check if it engages and kicks compressor in, DO NOT RUN COMPRESSOR FOR ANY TIME, or you'll seeze it without proper oil in the system. if it kicks in - good for you. if it's not - clutch is toast or compressor is seezed. btw, you need to know which terminal on the clutch connector is + and which is -, for obvious reasons.
now, being able to engage compressor, start the engine, turn AC on (on some cars it won't turn on if temp regulator is not in cold zone), turn blower on (it won't start if the blower is not on), connect your can of freon/oil mix to LOW side of the system(if you want to do seperate freon and oil, do oil 1st), and start charging it IN SHORT BURSTS. point is not to keep compressor crancking without lubrication or.... that's why you need 2 sets of hands - one charges, one crancks compressor. charge/crank/5 seconds/stop, and so on. at some point of doing so, you should notice that compressor runs by itself. this is good news, as you built up enough pressure in the system for pressure switch to pick up and give compressor green light. if you have a visor in the sytem, you check on charge level by looking at the stream - it should be clear flow, slightly greyish. if you have foam or lots of bubbles in it - charge some more. or you can do pressure tests etc like recommended.
some stores sell AC conditioner that can be added to the system. what happens when system sits unused for long time, fluid coagulates and sediments in narrow passages, glogging lines and heat exchange radiator. so freon does not circulate anymore.
thus, TO MAINTAINE SYSTEM RUNNING PROPERLY, AC HAS TO BE TURNED ON EVERY MONTH FOR ABOUT 15 MINUTES, REGARDLESS OF THE SEASON, simply to avoid this condition. AC conditioners supposed to remove that gunk. good luck.

Last edited by ukrkoz; 04-24-08 at 08:58 AM.
Old 04-24-08, 08:43 AM
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By not running "Compressor". You may have a bad relay or pressure switch. But "ODDS" are freon.You have a leak some where! You need to find it, repair or replace. Mine is over 8 years old. and still going strong.
As Speedwrench said take it to shop to find out where leak is. Some times you can look around and find out where it is. It will be wet with oil around it. Some times a broken line. If it's all gone ( freon) you have to repair and pull vacum and recharge.
I would try to borrow or buy some guages. Read the freon in there now. on low and high side. It is 134A freon.

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