Close



Page 1 of 2 12 LastLast
Results 1 to 25 of 27

Thread: AC woes

  1. #1

    Default AC woes

    Hello, all:

    Finally managed to install three new lines and the new compressor this week. I flushed out the evaporator and the condenser. And they are clean. All sealed up and looked good. Pulled a vacuum and it held. Added about 8 ounces of PAG 46- its an R134a car now. Hooked up the manifold and began to recharge the system. It took maybe ten ounces of R134 and stopped taking any more. Compressor clutch would turn on for half a second then off for three. Maybe did this for three minutes. I stopped so as not to destroy anything.

    But maybe I did. Any ideas why it will not take in any more R134? I added the PAG to the compresoor before installing the manifolds. And all gaskets are new and were lightly coated with PAG during install. Only option is to try a shop and vac it out. Unless I did something wrong.

    Getting hot and definitely need good ac this summer.

    Thanks.

  2. #2
    Moderator wraithracing's Avatar
    Join Date
    Jun 2010
    Location
    Grand Junction, CO/RR TX
    Posts
    14,206

    Default

    First what did you vacuum the system down to?

    Next, I almost always have to jumper the low pressure switch on the accumulator to get it to pull enough Freon into the system to start. Once the clutch will stay engaged for a bit, I will unplug the jumper and hook it back up to the switch. Then I continue to add Freon to the required amount and/or pressure readings.

    I often have to put the Freon cans into a cup with warm water to get them to transfer into the system. Otherwise they will often freeze up and barely feed into the A/C system.
    ​Trey

    "I Don't build it hoping for your approval! I built it because it meets mine!"

    "I've spent most of my money on Mustangs, racing, and women... the rest I just wasted."

    Mustangs Past: Too many to remember!
    Current Mustangs:
    1969 Mach 1
    1979 Pace Car now 5.0/5 speed
    1982 GT Stalled RestoModification
    1984 SVO Still Waiting Restoration
    1986 GT Under going Wide Body Conversion Currently

    Current Capris:
    1981 Capri Roller
    1981 Capri Black Magic Roller Basket Case
    1982 Capri RS 5.0/4spd T-top Full Restoration Stalled in TX
    1984 Capri RS T-top Roller
    1983-84 Gloy Racing Trans Am/IMSA Body Parts

  3. #3

    Default AC woes

    I second everything above ^

    Another thing I tried recently was a handy tip from JA Cook. Pasted his comments below as he explains way better than I can:

    “When charging a system from scratch, I pull a deep vacuum (with a proper vacuum pump), then charge into vacuum on the high side, with the can inverted, to charge liquid instead of gas. This does not damage anything, or pose a safety hazard, because the compressor is not running. Once the flow stops, I then close the high-side valve on my manifold set, and open the low-side valve. At that point the system has enough pressure to engage the compressor clutch. I finish off with the can upright to avoid putting liquid into the low side. To keep the can pressure up, I place the can in the path of radiator airflow.”

    I did this recently on a vintage thunderbird with excellent results.

    Keep us posted on how it goes.
    84.5 GT Convertible Build Thread
    86 LX Coupe

  4. #4
    FEP Member
    Join Date
    Oct 2017
    Location
    south-central WY
    Posts
    251

    Default

    I third the above. If you have a gauge set or even a low pressure gauge on the can, you would see the low side pressure rise until the compressor cuts in. Then the low side pressure drops quickly until the low pressure switch cuts the compressor out. Over and over and over. As the system fills, the compressor will run longer before cutting out.

    As long as the can is cooler than ambient, the system is still taking refrigerant, and cooler ambient temperature prolongs the process. Warming the can, as noted above, speeds the process.

  5. #5
    FEP Power Member slow84lx's Avatar
    Join Date
    Apr 2006
    Location
    Dallas, TX
    Posts
    1,562

    Default

    Good advice here.

  6. #6
    FEP Senior Member
    Join Date
    Dec 2016
    Location
    Grand Rapids, MI
    Posts
    721

    Default

    What all is said above. Depending on the capacity of the system it can take time. I am assuming you are using the correct can tap with the new self sealing can? I wasn't paying attention a couple of years ago and tried to use one of my old taps on one of the new cans. Didn't work so well.

    Usually with a vacuum on the system I can get enough initial charge so the system engages the compressor. As mentioned, it might engage/disengage as the high side rises and the low side drops. I had an Explorer I was working on a couple of weeks ago that took 48 ounces of refrigerant. I was probably halfway through the second can before the compressor would stay on constantly. As also mentioned, if you can feel the can is cold then refrigerant is flowing. I usually shake the can while it is charging. Not sure if it does anything constructive, but it makes me feel better about myself and gives me something to do rather than standing still and watching the gauges.

    Don't be surprised if it takes several minutes to feed a 12 ounce can in. It probably isn't going in as quickly as you might think. Have patience. As long as the compressor isn't making any strange noises it is probably okay.

    If you didn't start with a vacuum on the system then you need to vacuum it down and start over.
    '89 XR-7 5 Speed
    '95 SC 5 Speed
    '91 Crown Vic P72 351W
    '97 Thunderbird
    '85 Ford LTD Squire

  7. #7

    Default

    Thanks for the advice everyone. Most appreciated.

    I vacuumed the system down to about 22 in Hg according to the gauge. Held that for at least fifteen minutes, maybe closer to twenty.
    I did jumper the pressure switch contacts but not at first. Compressor sounds very good, no weird noises.
    There is a sight glass on the gauge manifold and I could see refrigerant flowing but it gradually slowed. That's when I jumpered the contacts and it helped slightly for about a minute. That's when I decided to stop. Can did get very cold. I had no leaks as I used newer cans and the valve to open the can. I wonder if the can was actually empty despite feeling as if there was a small amount left. Or the valve gummed up.
    I'll try again. I was more worried about the PAG oil than anything else. Not sure about using the high side port. Not too expereinced at this but sounds like its worth a shot.
    What should be a ballpark total charge of 134a? Factory sticker says 2 pounds but thats R12. Last time I believe the system took over two cans, maybe 26 ounces. But that was a while ago.
    Thanks again.

  8. #8
    Moderator wraithracing's Avatar
    Join Date
    Jun 2010
    Location
    Grand Junction, CO/RR TX
    Posts
    14,206

    Default

    Typically you want to pull a deep vacuum on the A/C system shooting for 29.92 hg (sea level adjust for your altitude). Depending on your altitude above sea level you may not be able to get a full charge into the system only pulling it down to 22. Its also possible at that pressure there could still be moisture in the system, again just an FYI not a criticism.

    Generally speaking 134a charging amounts compared to R12 are @ 70-80% Since you have the factory sticker showing the # of pounds needed.

    Formula: (R12 Charge Specification x 0.9) – 0.25 lbs. = R134a Charge Level

    (2 lbs. x 0.9) – 0.25 lbs. = 1.55 lbs. That should get you pretty close to what the system needs. Keep in mind that with R134a you are better to be slightly undercharged than overcharged. The system will cool better undercharged than overcharged. Again the key being slightly!

    I generally add charge until the compressor stocks cycling at idle or at a slightly elevated idle. Then I watch my gauges and my temperature gauge in the middle A/C vent. System on Max Cool, but fan one speed below Highest setting. If I am not cooling well enough inside, I will continue to add charge (up to the maximum calculated amount) until I get the coldest temp out of the vent. Small additions of charging and let the system stabilize for a couple of minutes. If you add charge and the temp goes up. Stop immediately and don't add any more. That usually tells you the system is maxed out on charge and any additional charge even up to the calculated amount will most likely decreasing the cooling of the A/C system. Hope this helps!
    ​Trey

    "I Don't build it hoping for your approval! I built it because it meets mine!"

    "I've spent most of my money on Mustangs, racing, and women... the rest I just wasted."

    Mustangs Past: Too many to remember!
    Current Mustangs:
    1969 Mach 1
    1979 Pace Car now 5.0/5 speed
    1982 GT Stalled RestoModification
    1984 SVO Still Waiting Restoration
    1986 GT Under going Wide Body Conversion Currently

    Current Capris:
    1981 Capri Roller
    1981 Capri Black Magic Roller Basket Case
    1982 Capri RS 5.0/4spd T-top Full Restoration Stalled in TX
    1984 Capri RS T-top Roller
    1983-84 Gloy Racing Trans Am/IMSA Body Parts

  9. #9

    Default

    Thanks again for the info.

    I tried again yesterday, been a little busy. Same result. No refrigerant flowed through the sight glass but the gauges on the manifold worked well. Both registered normal and the compressor cycled a few times like before, then stopped so I stopped as well. So there is a slight charge in the system, then it stops. I'm wondering if the manifold set has a clog as I unfortunately used R134a with some kind of leak stop gunk in it. And maybe I hogged up the compressor, too. I vacuumed the system, then removed the compressor and dumped out some of the PAG oil- thought I might have too much in it. Reinstalled and you know the result.
    Maybe that is all it is. The system is trying to pull in R134 but can't. I can try to clean the hose but at this point, might be starting over, eh?

    Thanks again everyone.

  10. #10

    Default

    I checked the hose just now. Not clogged at all. So the system is broken, contaminated, who knows. Compressor might have a warranty, not sure. Bought it last fall. Its new, but not US made. I think it and the lines I replaced are all Four Seasons brand.
    Might the cycling pressure valve be at fault? If memory serves it is a Ford product and for R134a. I do have a foreign made spare but will have to check both. If the compressor starts to cycle with the pressure switch still connected, not jumpered, maybe that's the culprit?
    I'll keep at it.

  11. #11
    Moderator wraithracing's Avatar
    Join Date
    Jun 2010
    Location
    Grand Junction, CO/RR TX
    Posts
    14,206

    Default

    Quote Originally Posted by Magnetic82 View Post
    If the compressor starts to cycle with the pressure switch still connected, not jumpered, maybe that's the culprit?
    I'll keep at it.
    I am confused by your statement. You should only jumper the pressure switch when needed to get the initial can of freon into the system. Once the system has enough freon in it to cycle the compressor, you should plug the switch back in and allow the switch to control the compressor. As the compressor pulls the system pressure down on the low side, the pressure switch will cut power to the compressor. Otherwise the system will freeze up the evaporator core and orifice tube. The system pressure rises and then the pressure switch will energize the compressor clutch and the whole process starts again. This is the way it works when the system is low on charge and when driving down the road with additional RPM. When charging the system in your driveway, most often you will charge the system until the clutch stops cycling and the system is cooling at the correct temperature in the cabin.
    If the clutch is cycling on and off in short order usually that is because the charge is too low. If it cycles off on long intervals, that can be normal if the system is cooling properly in the cabin. Also once the initial charge is introduced into the system, you have to have the compressor engaged in order to pull any additional charge in. The can pressure is not enough to overcome the system pressure.

    Last item, the cycling switch is adjustable. There is a small flat headed screw in the middle of the switch that can be turned (slightly) to adjust the pressure point that the switch cycles on/off. Sometimes when converting to 134a adjusting the switch is needed in order to get the system to cool correctly. Generally only about 1/4 turn either direction is needed. I don't think I have ever adjusted one more than that. Hope that helps and good luck!
    ​Trey

    "I Don't build it hoping for your approval! I built it because it meets mine!"

    "I've spent most of my money on Mustangs, racing, and women... the rest I just wasted."

    Mustangs Past: Too many to remember!
    Current Mustangs:
    1969 Mach 1
    1979 Pace Car now 5.0/5 speed
    1982 GT Stalled RestoModification
    1984 SVO Still Waiting Restoration
    1986 GT Under going Wide Body Conversion Currently

    Current Capris:
    1981 Capri Roller
    1981 Capri Black Magic Roller Basket Case
    1982 Capri RS 5.0/4spd T-top Full Restoration Stalled in TX
    1984 Capri RS T-top Roller
    1983-84 Gloy Racing Trans Am/IMSA Body Parts

  12. #12
    FEP Power Member
    Join Date
    Nov 2007
    Location
    San Mateo, CA
    Posts
    2,271

    Default

    The pressure switch from Motorcraft comes adjusted for R12. I see 4seasons offers one for R134.
    Fox Body/3rd Gen MCA Gold Card Judge
    84 SVO 24K miles, 85 Mclaren Capri Vert. 84 GT Turbo Vert.
    88 Mclaren Mustang Vert 20K miles, 89 Mustang LX Sport Vert,
    03 Mach 1 7900 miles, 74 Mustang II, 69 Mustang, 67 Mustang, 07 GT500,
    14 Mustang CS/GT, 15 F150 FTX Tuscany, 16 F250 Crewcab, 67 Tbird 47K miles

  13. #13

    Default

    I've had issues using newer epa approved self closing cans. I have a couple cheap light blue screw on caps from the parts store. Both don't work at all. They never open the valve in the can tip. I have a brass adapter for these new cans. It looks like the old screw in the piercing types, but instead it pushes in the valve to open it
    This also doesn't work all the time. Many times I switch between cans. If you screw in the tap and then open the low side and see nothing entering the sight glass, I'll bet the tap isn't opening the can valve. I've had this issue using mostly Walmart super tech and another brand from there. I can usually get them to work, eventually. Try loosening the hose at the manifold to the can tap after you " open" the can valve. If it flows weak or nothing, the can isn't open
    And like everyone else said, emptying a can take a long time. Keep heating it up

  14. #14

    Default

    Thanks, all. I'll have another go at it this weekend. Could be the can.

    On another note, I have the original compressor and a spare I found at Carlisle. I opened up the original 6p148a and am trying to follow the manual and clean it up and reseal it. Here's where I'm at on this project. Well I can't upload photos for some reason.
    I have the front head off the compressor but nothing came with it. The gasket and seal stayed with the valve plate. Plus the shaft seal is of course still there and I'm not sure how to remove the plate at this point. Manual says it all comes off in one shot, then remove the shaft seal. Don't want to damage anything. And mabe I'm just reading things wrong. How does the seal come off at this point? I doubt it was reassembled wrong a few years ago when the compressor was resealed. It worked for a short while, then quit.

    Thanks everyone.

    Cheers

  15. #15

    Default

    Well it came apart easily after a little effort. But the gaskets stayed with the valve plates. I'd post some pictures but still cannot- not sure why.
    There is some corrosion on the top of one of the pistons but they do move well, not locked up at all. I cleaned the whole thing with parts cleaner but there is some staining on the interior parts. Not sure if this thing is saveble but I have a spare that hasn't been opened up.
    What's the call on compressors for repair or tossing it? The pistons appeared to seal when I cleaned the body and moved them around to drain out the cleaner. And the gaskets? Perhaps soaking them will release them?
    Plus I need to take the body apart and replace the center gasket. Since that involves the pistons, might want to think about that.
    Hopefully I can get one of these things running and at least have a spare when the time comes.
    Might try to recharge the system on the car tomorrow morning.
    Thanks again.

  16. #16

    Default

    Here's a thought about the recharging problem with my new compressor on the car now.

    Could the manifolds be blocked or otherwise stuck? Is there a good way to check them? I need to pull them anyhow and add a few ounces of oil to the compressor so I can check them off the car.

    Thanks.

  17. #17

    Default

    I'm no expert, and know very little about charging a system.... But aren't you just supposed to put part of the oil in the compressor and distribute the rest throughout the system? Maybe there's too much oil in the compressor at once...?

  18. #18

    Default

    I thought that might be the case. So the compressor right now doesn't have enough in it. As it isn't working I left it that way. Too much charge is almost as bad as not enough. Correct. I also think there may be a problem with the accumulator and attached line. Not sure. Don't plan to take it apart just yet. May try a new one in the future. And basically start all over again.

    I did manage to disassemble the old compressor the whole way right down to the pistons. Wasn't as bad as I thought it would be. The inside surfaces show some staining and rough spots but not what I would care wear. And the machining on the top of the pistons is a little rough. But the whole thing works. All cleaned up as best I could. This compressor leaked from the middle body seam and if the system at that time was over chraged or experienced high pressure internally due to a blockage, say from the manifolds, that would explain why it failed. Of course, even if I manage to reassemble the thing I'm not sure how I would test it without intalling it back on the car and trying to charge the system. And if I missed any gunk then presto, right back to square one. But it was good to take it apart. When I can post photos I will.

    Thanks again.

  19. #19

    Default

    I decided to disassemble another spare compressor and it was in much better shape inside. Finally managed to reassemble it following the shop manual. A little bit of a chore but took maybe an hour or so. I need to reinstall the shaft key and then the clutch and I can then begin to test it and hopefully install this one in the car and try for a system recharge. What's the best way to put the key back in properly? Of course I used new seals and hardware and properly lubed the parts during reassembly. The manifilds that came with this spare are in good shape so I plan to use them. I'll keep everyone posted on this. Definitely need AC now.

  20. #20

    Default

    Well after another few days and hours outside...
    Still no AC. The system takes in about ten ounces of R134a and then leaks around the suction line connection to the compressor. And that happened twice with two different suction lines. Proper oil added, condenser and evaporator thoroughly cleaned out, new lines underhood, and the resealed and lubed compressor. Good manifolds and valves also. Even new R134a adapters for the high and low ports. Jumpered the pressure switch to get the system to take in the first bit but had to jumper the switch almost entirely to get it to drink in any amount. Then presto- a leak.

    Guess the system is blocked. But which hose? Probably need all three now. So much for Four Seasons junk. Also tired of spending money on this thing and no results. Too hot to drive without AC now. And the shops around here are a joke.
    Suggestions welcome but I'm getting tired. Would be nice to fix something right the first time.

    Cheers.

  21. #21
    FEP Power Member slow84lx's Avatar
    Join Date
    Apr 2006
    Location
    Dallas, TX
    Posts
    1,562

    Default

    Have you verified that the threads on each side of the leaking connection are in fact the same on each side? I would look at this closely first for a mis-match.

    Did this system hold a proper vacuum for an extended time prior to charging?

    I've had good luck with the Four Seasons brand back in the '90's. I have no idea what their current quality is like. The last A/C system I worked on was my 1992 F-150. I did a complete replacement of the entire system with parts for a later model that used R134A. All new parts from a combination of Napa & Rock Auto. No issues at all and that truck still blows cold after 4 years without any further maintenance.

    Keep your head up. You will prevail!

    Jonathan

  22. #22

    Default

    Its odd that with two suction lines I had a leak in the same place. Might be a thread problem. I sent the one hose back for a refund but need to check. I'm running a vacuum right now. I wanted to look at the compressor as well. Don't think I reassembled it wrong but might be worth a look. I have another compressor still disassembled and it appears to only go back together one way. Maybe one of the hoses is blocked. Four Seasons is China now so quality is anyone's guess. I can recheck all the connections also. Definitely will keep at it but (sigh) it does grow old. Summer might be over by the time this thing works.

  23. #23

    Default

    Attempt number, 4? Not sure, I lost count.

    I have another replacement suction line with the accumulator. I added oil to the compressor and there should be at least 4 ounces in it if not more. I think I may need maybe 2 more ounces and would like to add it to the accumulator. I may have added it incorrectly in the past. The shop manual says to add oil through the Schrader valve, which I cannot take apart. Is it possible to add it to the smaller tube on the tank? That may be the blockage in the system keeping the refrigerant from flowing. I want to check the other lines and will probably flush the condenser and evaporator again if I don't run out of flush. I've had a vacuum pulled on it for about 40 minutes today at 24 in/Hg. I will of course coat the gaskets with oil during reassembly.

    I have a new Ford cycling pressure switch. Its likely set up for R12. Which way should I adjust the small screw in the switch and for how far for R134a? Looking at it with the outside locking tab up, the screw seems to be pointing to 2PM/ 8PM, if that makes sense.

    Any ideas and suggestions at this point are most welcome. Should be in the low 90s all next week. Might need the AC.
    Maybe I should move to Alaska.

    Thanks all.
    M

  24. #24
    FEP Senior Member
    Join Date
    Dec 2016
    Location
    Grand Rapids, MI
    Posts
    721

    Default

    Is 24 in/Hg all that your vacuum pump can pull on any system or just this? You usually want to get down to or as close to 29.92 as possible. When you close the valves and turn the pump off how long will it hold?

    When I am starting from scratch on a new system I usually add half of the oil to the compressor and half to the accumulator.
    '89 XR-7 5 Speed
    '95 SC 5 Speed
    '91 Crown Vic P72 351W
    '97 Thunderbird
    '85 Ford LTD Squire

  25. #25

    Default

    I'll try to vacuum the system down again this weekend. It usually holds at near 26 inches and it holds that for a while. The last time I tried it only went to maybe 24 inches and did not hold long after I closed the valves. I may not have attached the hoses securely, was getting frustrated and tired at that point. Definitely will try again. I'm thinking of replacing the condenser and evaporator anyway. That would help replace the tape deck while I have the dash off. Who knows.

Page 1 of 2 12 LastLast

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •