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  • nsubre
    replied
    When you convert from R12 to R134a, you also have to remove the mineral oil in the compressor and replace it with synthetic refrigerant oil, since the R134a won't mix with the mineral oil. If you leave the mineral oil in the compressor and add the synthetic oil, it will make a huge mess.
    Larry

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  • mtony
    replied
    Originally posted by RAD2LTR View Post
    Thread revival...

    Its been hot here lately and I've been thinking some a/c might be nice. The a/c has never worked in the car since I bought it, however it was recharged in November 2011, only a couple weeks before I bought it. (Since it was in Canada, its hard to say if it was working then or not. The air temp was colder than the a/c temp so either way, it was going to feel cold.

    I've done a little poking around, but the truth is, I honestly don't know if it has a charge on it or not. The light lights up when pressed, I can hear the compressor kick on, but the temp doesn't change. The aux fan also doesn't kick on with the a/c button pushed, but it does run when the temp gets high enough at idle. I replaced the switch for it last year (It didn't work at all last year), I think I replaced both switches on the thermostat now that I think about it. The metal pipes that come from the compressor also don't seem to change temp either. I assume one would be warm and the other very cold. As a side note, during the winter I've kicked the a/c on to defog the windows, but it hasn't really done anything. This leads me to believe something isn't opening or closing.

    My hunch is, its a valve issue and perhaps a tired air drier. Its still an R12 system according to the receipt I have from the previous owner. I do cycle the system on and off about once a week (I let it run for 15 minutes or so every time) even though its never worked in an effort to keep the seals lubed. My guess is that the pressure is low, but from the sound of it, if it were low, the compressor won't engage. All the wires appear to be plugged in where they should. I've never delt with a/c before so I'm a little at a loss here.

    Thanks,
    Will
    Will,

    If you plan to do A/C work on your own, you'll have to start by getting a set of gauges so you can measure both low and high side pressures. That will give an idea of what is wrong with the system.

    Leave a comment:


  • RAD2LTR
    replied
    Thread revival...

    Its been hot here lately and I've been thinking some a/c might be nice. The a/c has never worked in the car since I bought it, however it was recharged in November 2011, only a couple weeks before I bought it. (Since it was in Canada, its hard to say if it was working then or not. The air temp was colder than the a/c temp so either way, it was going to feel cold.

    I've done a little poking around, but the truth is, I honestly don't know if it has a charge on it or not. The light lights up when pressed, I can hear the compressor kick on, but the temp doesn't change. The aux fan also doesn't kick on with the a/c button pushed, but it does run when the temp gets high enough at idle. I replaced the switch for it last year (It didn't work at all last year), I think I replaced both switches on the thermostat now that I think about it. The metal pipes that come from the compressor also don't seem to change temp either. I assume one would be warm and the other very cold. As a side note, during the winter I've kicked the a/c on to defog the windows, but it hasn't really done anything. This leads me to believe something isn't opening or closing.

    My hunch is, its a valve issue and perhaps a tired air drier. Its still an R12 system according to the receipt I have from the previous owner. I do cycle the system on and off about once a week (I let it run for 15 minutes or so every time) even though its never worked in an effort to keep the seals lubed. My guess is that the pressure is low, but from the sound of it, if it were low, the compressor won't engage. All the wires appear to be plugged in where they should. I've never delt with a/c before so I'm a little at a loss here.

    Thanks,
    Will

    Leave a comment:


  • mtony
    replied
    Just thought I'd update this thread since I just finished this project. I ended up having my compressor rebuilt by Polar Bear Inc. Replaced the two hoses going into and out of the compressor. Replaced the evaporator (found it was leaking when i pulled it out before replacing the expansion valve). Replaced the dryer and then pulled a vacuum.

    Well the vacuum wouldn't hold so I rechecked all my connections and this time I put Nylog on all the fittings. When I took the expansion valve off of the evaporator, I realized that the preinstalled expansion valve I purchased from Autohaus AZ didn't have O-rings. I had assumed it did since the evaporator came with the expansion valve installed on it and the bolts were tight when i checked them.

    After I got it all buttoned up, I pulled vacuum for 45 minutes and let it sit overnight. I then pulled vacuum for another 30 minutes and started the recharge. Most of the first can was sucked in by the vacuum. I then started the car and the A/C to finish the first can and started on the second. Halfway through the second can (total of about 18oz) my gauges were reading a low side of 30 and a high side of 200 with an ambient temp of 80. The vent temps were in the mid 50s. Fearful of blowing the compressor again, I stopped charging and took it for a spin and am happy to report that my vent temps were 46 degrees with an ambient temp of around 85.

    So although it seems like my system didn't take a full charge (I expected to charge it with 28oz or so) it is cooling well and the pressures seem correct.

    Leave a comment:


  • RDCD12
    replied
    Originally posted by blyguy View Post
    That sounds like a nightmare. You've got a lot of patience and perseverance to get through that.

    The smaller A/C parts seem to be a lot cheaper at the warehouse autoparts places, like azautohaus. I went through their prices and I think they are cheapest right now (no affiliation, of course) plus they have free shipping fro > $50 orders.

    Behr recevier/drier $17.53
    Expansion valve $17.53
    R134a conversion kit (o rings, seals, etc) $18.95
    Low pressure switch $6.70 (!!)
    High Pressure switch $18.02
    Evaporator temp sensor $29.33

    HTH

    Bryant
    I'm in Jersey, and the heat just kept killing me. Thus driving the perseverance. lol....

    Leave a comment:


  • blyguy
    replied
    That sounds like a nightmare. You've got a lot of patience and perseverance to get through that.

    The smaller A/C parts seem to be a lot cheaper at the warehouse autoparts places, like azautohaus. I went through their prices and I think they are cheapest right now (no affiliation, of course) plus they have free shipping fro > $50 orders.

    Behr recevier/drier $17.53
    Expansion valve $17.53
    R134a conversion kit (o rings, seals, etc) $18.95
    Low pressure switch $6.70 (!!)
    High Pressure switch $18.02
    Evaporator temp sensor $29.33

    HTH

    Bryant

    Leave a comment:


  • RDCD12
    replied
    Originally posted by mtony View Post
    Wow, sorry to hear that. My head is starting to hurt already just from seeing what's involved with replacing the expansion valve.

    If you need instructions let me know. I can pdf you the alldata stuff. Not the end all, but it helps.

    If you need parts let me know as well, BMW's prices on some of this is outrageous. They wanted $200 for the receiver dryer that I found for less than a fifth of the price.

    Leave a comment:


  • mtony
    replied
    Originally posted by ARDD12 View Post
    I just went through this on my own.

    88 E30, tried freeze 12 and it worked till the compressor took a sh*t.

    That was only the beginning of the nightmare.

    The only compressors I found available were really geared for R134 and I had no choice but to make the painful switch.

    Piece by piece this was my experience:

    - Replace Compressor
    - Replace Lines with BMW R134a compatible lines
    - Replace Receiver/Dryer with Updated BMW One
    - Replace Pressure Switch with Updated BMW One ( The previous pressure switch is no longer available through BMW, and you need to purchase a wiring kit as well or make your own. Easily made )
    - Replace A/C Evaporator with Updated BMW One

    This is when my car really started to hate me:

    At some point in time if your BMW was serviced by BMW there may be a added fuse block in the wiring for your A/C. I found this out as my button would not light up anymore, thus my A/C wasn't receiving power and wouldn't turn on.

    Looking at the button, I noticed that some of the terminals were becoming "blackened". Possibly a sign that the switch is bad or going bad. I ordered a replacement one, put it in and much to my surprise, still wouldn't light up.

    I had already checked fuses and measured resistance on the major wires so this left me stumped. Gave up for a while, luckily enough for me the radio was annoying me as well. One day while rewiring the radio I found a black wire that led to an inline fuse. Would you know... it connected to the switch. Replaced the fuse, A/C worked. Since then I've found that the inline fuse block needs to be replaced as the shock from every day driving has worn it out.

    But these were my A/C lessons. Hope I saved someone a headache one day.
    Wow, sorry to hear that. My head is starting to hurt already just from seeing what's involved with replacing the expansion valve.

    Leave a comment:


  • RDCD12
    replied
    I just went through this on my own.

    88 E30, tried freeze 12 and it worked till the compressor took a sh*t.

    That was only the beginning of the nightmare.

    The only compressors I found available were really geared for R134 and I had no choice but to make the painful switch.

    Piece by piece this was my experience:

    - Replace Compressor
    - Replace Lines with BMW R134a compatible lines
    - Replace Receiver/Dryer with Updated BMW One
    - Replace Pressure Switch with Updated BMW One ( The previous pressure switch is no longer available through BMW, and you need to purchase a wiring kit as well or make your own. Easily made )
    - Replace A/C Evaporator with Updated BMW One

    This is when my car really started to hate me:

    At some point in time if your BMW was serviced by BMW there may be a added fuse block in the wiring for your A/C. I found this out as my button would not light up anymore, thus my A/C wasn't receiving power and wouldn't turn on.

    Looking at the button, I noticed that some of the terminals were becoming "blackened". Possibly a sign that the switch is bad or going bad. I ordered a replacement one, put it in and much to my surprise, still wouldn't light up.

    I had already checked fuses and measured resistance on the major wires so this left me stumped. Gave up for a while, luckily enough for me the radio was annoying me as well. One day while rewiring the radio I found a black wire that led to an inline fuse. Would you know... it connected to the switch. Replaced the fuse, A/C worked. Since then I've found that the inline fuse block needs to be replaced as the shock from every day driving has worn it out.

    But these were my A/C lessons. Hope I saved someone a headache one day.

    Leave a comment:


  • mtony
    replied
    Originally posted by 02fanatic View Post
    That sucks! Sorry to hear....years ago the compressor on my M5 "blew" with a loud "pop" while driving.....ended up being a blocked condenser. After buying another compressor, condenser & receiver drier....having the system evacuated and recharged by the dealer...all was well.....System is still R12. So, you might start with the condenser...my bet is it's blocked. A professional can leak test, flush and pressure test to isolate the problem. Just be sure you find someone who will be good working around your "baby"....I hate the thought of any typical bonehead a/c tech fooling with my cars. Ask me who broke the driver seat bolster in the M5!?
    I know what you mean. My baby has 46K miles on it and the original paint is in awesome condition. I usually try to do all the work on it myself, because most mechanics don't seem to care. I've just never done A/C work and don't want to end up screwing something else up after paying for the rebuild. I'd rather they make sure the lines are clear before hooking everything back together.

    Leave a comment:


  • 02fanatic
    replied
    That sucks! Sorry to hear....years ago the compressor on my M5 "blew" with a loud "pop" while driving.....ended up being a blocked condenser. After buying another compressor, condenser & receiver drier....having the system evacuated and recharged by the dealer...all was well.....System is still R12. So, you might start with the condenser...my bet is it's blocked. A professional can leak test, flush and pressure test to isolate the problem. Just be sure you find someone who will be good working around your "baby"....I hate the thought of any typical bonehead a/c tech fooling with my cars. Ask me who broke the driver seat bolster in the M5!?

    Originally posted by mtony View Post
    Well I took it out for a spin this morning after checking pressures again which were about the same. The air was cooling slightly with vent temps of around 70 on an 82 degree morning. Condensation dripping, and everything seemed fine. Well after I got back into the garage, all the refrigerant blew out with a cloud of gas. Scared the crap out of me. Form looking from above, it looks like the compressor blew a gasket and spilled everything out through a seam. Guess I need a new one. Question is, is there something else along the system that caused the compressor to fail?

    Guess I'll be getting the compressor rebuilt (Polar Bear?) and then I'll take it to a pro to get the lines blown, a new expansion valve and dryer installed, and then a charge.

    Leave a comment:


  • mtony
    replied
    Well I took it out for a spin this morning after checking pressures again which were about the same. The air was cooling slightly with vent temps of around 70 on an 82 degree morning. Condensation dripping, and everything seemed fine. Well after I got back into the garage, all the refrigerant blew out with a cloud of gas. Scared the crap out of me. Form looking from above, it looks like the compressor blew a gasket and spilled everything out through a seam. Guess I need a new one. Question is, is there something else along the system that caused the compressor to fail?

    Guess I'll be getting the compressor rebuilt (Polar Bear?) and then I'll take it to a pro to get the lines blown, a new expansion valve and dryer installed, and then a charge.

    Leave a comment:


  • mtony
    replied
    Originally posted by blyguy View Post
    This is a good guide on polarbearinc.com- it sounds like the compressor isn't 100%. I think any issues in the expansion valve or evaporator would give you extremely elevated high side readings. The entire troubleshooting guide on their website is also very informative.

    http://www.polarbearinc.com/Trouble9_gaugereadings.htm
    Thanks for the link blyguy. I'll take a look.

    Leave a comment:


  • blyguy
    replied
    This is a good guide on polarbearinc.com- it sounds like the compressor isn't 100%. I think any issues in the expansion valve or evaporator would give you extremely elevated high side readings. The entire troubleshooting guide on their website is also very informative.

    http://www.polarbearinc.com/Trouble9_gaugereadings.htm

    Leave a comment:


  • mtony
    replied
    So I pulled a vacuum and it held. Jumped the low pressure switch at the harness and started recharging. Got about 30oz. of refrigerant in and my low side pressures got to 35 but the high side got up to only about 80psi. and the air wasn't cooling much at all (78 F on a 90 F day). Does this mean that the compressor is bad, or could there be other causes for the low high side pressures?

    Leave a comment:

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