old-tank Posted April 5, 2023 Share Posted April 5, 2023 First use this year and it ain't cooling. Vent temperature barely 65°. Line pressures unchanged no matter what the charge level (40 on the low side and 120 on the high side). The last time I saw the situation there were broken reed valves. So I pulled the cylinder head and found no problem with the reed valves. Planned to recharge it again but there is an apparent leak in the system now.(fooey). No problem just add a little refrigerant and get my halogen detector and see where the leak is. 10 years since the last use and the batteries are all corroded (shucky darn). Rigged an external 6 volt battery and that only produced copious smoke (dadgummit). New halogen detector on order... 1 Link to comment Share on other sites More sharing options...
NailheadBob Posted April 5, 2023 Share Posted April 5, 2023 @old-tank If you want to send back the leak detector you ordered, you can use my halogen leak detector for FREE, just pay for the shipping and insurance to you and back to me. Bob Link to comment Share on other sites More sharing options...
old-tank Posted April 5, 2023 Author Share Posted April 5, 2023 13 minutes ago, NailheadBob said: @old-tank If you want to send back the leak detector you ordered, you can use my halogen leak detector for FREE, just pay for the shipping and insurance to you and back to me. Bob Thanks for the offer, the one I ordered is only $25 ...just have to see how it works. Link to comment Share on other sites More sharing options...
old-tank Posted April 7, 2023 Author Share Posted April 7, 2023 Well what do you know the cheap leak detector found the leak at the front. I worked on the back why is it at the front? Changed the seal and o-rings (detailed on my website). So now I'm back to where I started, no cooling and screwed up pressures. The refrigerant is going through the system unimpeded like the expansion valve is not working. Pulled the access panel and looked at the expansion valve. It is apparently a thermal expansion valve that is adjustable. Tested the bulb with an ice cube and it did change the pressures. Attempted adjusting the expansion valve with no change. Even though the expansion valve is attached to the system with flare nuts, they are completely inaccessible... With my tools. I would need a 1 inch and 7/16 in Crowfoot wrenches 12 point of course if that even exists. (Double shucky). Going to go drive a Buick just to relieve some stress and think about this s***. 4 1 Link to comment Share on other sites More sharing options...
EmTee Posted April 7, 2023 Share Posted April 7, 2023 10 hours ago, old-tank said: Well what do you know the cheap leak detector found the leak at the front. Which one did you wind-up buying? I think I need one in my toolbox... Link to comment Share on other sites More sharing options...
NailheadBob Posted April 7, 2023 Share Posted April 7, 2023 What are the A/C pressure readings? Amazon has several brands of 12 point crowfoot wrenches Bob Link to comment Share on other sites More sharing options...
old-tank Posted April 7, 2023 Author Share Posted April 7, 2023 3 hours ago, EmTee said: Which one did you wind-up buying? I think I need one in my toolbox... this one...batteries not included 1 Link to comment Share on other sites More sharing options...
old-tank Posted April 7, 2023 Author Share Posted April 7, 2023 2 hours ago, NailheadBob said: What are the A/C pressure readings? Amazon has several brands of 12 point crowfoot wrenches Bob Pressures: 40 low side and 100-120 high side no matter what the charge level. I have the same system in another car and it cools well (pressures: 20 low side and 150 high side) Or I could cut the end out of a box end wrench and make a flare nut wrench. Too cold today for A/C work, but just right to trouble shoot some power antenna issues... 1 Link to comment Share on other sites More sharing options...
EmTee Posted April 7, 2023 Share Posted April 7, 2023 4 hours ago, old-tank said: Pressures: 40 low side and 100-120 high side no matter what the charge level. Obstruction ahead of the compressor? Bad accumulator? You tried adjusting the orifice and there was no change; which makes me think it might be a restriction between the orifice and the compressor. I'm no refrigeration expert -- just looking at a schematic and thinking out loud... Link to comment Share on other sites More sharing options...
old-tank Posted April 7, 2023 Author Share Posted April 7, 2023 1 hour ago, EmTee said: Obstruction ahead of the compressor? Bad accumulator? You tried adjusting the orifice and there was no change; which makes me think it might be a restriction between the orifice and the compressor. I'm no refrigeration expert -- just looking at a schematic and thinking out loud... No restriction. A restriction would have the low side pressure real low and the high side pressure is real high. In this case the expected restriction that the expansion valve is apparently not present. 1 1 Link to comment Share on other sites More sharing options...
old-tank Posted April 12, 2023 Author Share Posted April 12, 2023 Liquid bypass solenoid. When the temperature setting of the thermostat is satisfied some of the refrigerant is diverted back to the compressor by the liquid bypass solenoid. This makes the system less efficient until it warms up and cooling is needed again. Anyhow I was working on something else and turned the key on and apparently air conditioner was on and low blower fan was running and heard the click of the compressor clutch and also heard a click of something under the passenger floor. Thinking it was referred noise from the clutch clicking I disconnected the power to the compressor and it was still there. Something is fouled up in the thermostat or associated parts. I have never heard a click before and it has been functioning as designed for many years and many tens of thousands of miles. On my other car the solenoid would engage before it was cool enough in the car so I disabled it by disconnecting the ground wire and regulate the temperature by cycling the clutch manually. So I disabled this one and now the system seems to be working and cooling fine with normal expected pressures. So it's not terminal after all. 4 1 Link to comment Share on other sites More sharing options...
NailheadBob Posted April 12, 2023 Share Posted April 12, 2023 I learn something new from Wille all the time, such a knowledgeable member. What were the new pressure readings with the ground wire disconnected? Bob Link to comment Share on other sites More sharing options...
KAD36 Posted April 12, 2023 Share Posted April 12, 2023 10 hours ago, old-tank said: Liquid bypass solenoid. Does that mean this isn’t needed or…. No expert either, never heard of it and to my knowledge not part of my aftermarket system. Link to comment Share on other sites More sharing options...
old-tank Posted April 12, 2023 Author Share Posted April 12, 2023 11 minutes ago, NailheadBob said: What were the new pressure readings with the ground wire disconnected? 20 low side; 150 high side. 3 minutes ago, KAD36 said: Does that mean this isn’t needed or…. No expert either, never heard of it and to my knowledge not part of my aftermarket system. Not used on any system after 55. Not needed as long as you are willing to cycle the compressor manually if the wife gets too cold. A/C in GM cars early on had the compressor running all the time and regulated temperature by various schemes to make the system less efficient. (liquid bypass solenoid; hot gas bypass; POA; VIR and others) Maybe it was too achieve a smoother operation vs cycling the compressor like other makes and aftermarket systems. 1 Link to comment Share on other sites More sharing options...
NTX5467 Posted April 12, 2023 Share Posted April 12, 2023 By the time we got tot the 1960s, a compressor which ran all the time, with capacity restrictors, was the norm for a "luxury" a/c system, whether GM or larger Chrysler platforms. It was not until the middle 1970s or so that Ford started to use an A6 compressor and POA valves, rather than their traditional cycling-compressor system. With all of the metal slinging around in a Ford FE or MEL engine, the additional load of a compressor kicking in didn't really faze the idle speed like it would on a GM or Chrysler engine, it seems. GLAD you got things figured out! NTX5467 1 Link to comment Share on other sites More sharing options...
NTX5467 Posted April 13, 2023 Share Posted April 13, 2023 Just curious, can those solenoids be replaced with something newer and/or better without re-engineering everything? Or is there a way to install a cycling switch on an existing pressure tap? NTX5467 Link to comment Share on other sites More sharing options...
old-tank Posted April 13, 2023 Author Share Posted April 13, 2023 2 hours ago, NTX5467 said: Just curious, can those solenoids be replaced with something newer and/or better without re-engineering everything? Not easilt 2 hours ago, NTX5467 said: Or is there a way to install a cycling switch on an existing pressure tap? Yes, but that works best with an orifice system not with a thermal expansion valve like this. I have time to do test it with all outside temperatures. 1 Link to comment Share on other sites More sharing options...
EmTee Posted April 13, 2023 Share Posted April 13, 2023 So, what is it in the dashboard control that is supposed to cycle that solenoid? Is there a bimetal coil thermostat? Glad you figured it out. Are you still running R-12? Link to comment Share on other sites More sharing options...
old-tank Posted April 15, 2023 Author Share Posted April 15, 2023 On 4/13/2023 at 5:46 AM, EmTee said: So, what is it in the dashboard control that is supposed to cycle that solenoid? Is there a bimetal coil thermostat? Glad you figured it out. Are you still running R-12? I haven't checked out the controls and I may not. No more R12... Using R152a for the last 15 years. 2 Link to comment Share on other sites More sharing options...
old-tank Posted April 20, 2023 Author Share Posted April 20, 2023 Here's some more totally useful information for everybody. The leak at the front of the compressor was due to a failure of the sealing interface. The carbon face seal that rides against the spinning seat is pushed against the seat by a very robust spring. That spring had totally lost its tension. It was completely retracted when I took it out. I could extend the seat and it stayed there I could push it back in and stayed retracted. That area does not get very hot but there is a very large magnetic field from the coil that activates the clutch. What turns the spring into malleable metal? Anyhow the new seal is doing its job and the thing is cooling well. 6 2 Link to comment Share on other sites More sharing options...
EmTee Posted April 20, 2023 Share Posted April 20, 2023 Hmmm... Springs do fatigue like that sometimes. I can't think of an obvious reason that the EM field would be a factor, but maybe someone else has an idea. I'd think that maybe there's some inherent run-out between the two surfaces that contains the spring. Could the constant compression/relaxation cycling of the spring eventually fatigue the metal? Seems like the compression/relaxation lengths would be small, but add some heat, EM and almost 70 years and maybe... 1 Link to comment Share on other sites More sharing options...
NailheadBob Posted April 20, 2023 Share Posted April 20, 2023 Great news on your success with the A/C, now you can just sit back and drive your nice cool car Bob 1 1 Link to comment Share on other sites More sharing options...
NTX5467 Posted April 21, 2023 Share Posted April 21, 2023 "Cool" in ways other than just interior temperature. NTX5467 1 Link to comment Share on other sites More sharing options...
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