A/c woes
#1
A/c woes
I've spent the past two weeks practically redoing my whole a/c system and chasing leaks. New compressor, condenser, evaporator, and accumulator. My high pressure pipe had a leak so I bought a kit from auto ac solutions and fixed that. Finally got it to hold a vacuum and charged it today. As soon as I removed the hose from the high pressure service port, all 2.5 cans of refrigerant blew out and filled my garage with vapor.
What the hell? Any idea what could have caused that? An a/c shop just installed that valve on my high pressure line last week.
What the hell? Any idea what could have caused that? An a/c shop just installed that valve on my high pressure line last week.
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Roorancher (04-23-2024)
#3
Member
Re: A/c woes
Was that R12 that blew out? That stuff (the real stuff) is pricey. Sounds like the schrader valve needle got stuck open. (like drive it) mentioned.
#6
Re: A/c woes
The fan switch complicates it a little bit because it's right in the middle. The wire harness is long enough to where it can be moved back towards the evaporator, so I told them to do that if needed.
This whole process has been an ordeal for sure. I have a new Four Seasons evaporator and a new Spectra condenser, but the connectors on both are off a bit from the originals, so using the original hard line is a challenge without bending the crap out of it and causing leaks.
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80schild (04-23-2024)
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#8
Re: A/c woes
the ac shop is going to make one basically like the 89-92 style with the rubber hose, but in the shape I need for my '87. Like I mentioned, the aftermarket evaporator connections are slightly different, so a flexible hose would be better I think. I hate having to bend anything to make it fit.
Last edited by 80schild; 04-23-2024 at 07:36 PM.
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1989karr (04-23-2024)
#9
Re: A/c woes
I thought I had posted this pic already, but here's the difference in the evaporators. You can see the chambered ends of the Four Seasons evap are smaller than stock, and the overall depth is less too. Extra foam is needed to make it snug. Connections are off a bit too.
#10
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Car: 90 Formula / T-tops
Engine: 305 TPI
Transmission: MD8
Re: A/c woes
BTW - you should pull a vacuum before loading the refrigerant. then see if the vac holds for 30 minutes and hour, what ever. in your case, you would have lost vac immediately. the vac removes air out of the system (bad stuff) and waiting 30 min proves you have no leaks. you need a vac gauge of course. which you need if you want to do your own work. can use it on all cars if you buy the right one.
#12
Re: A/c woes
BTW - you should pull a vacuum before loading the refrigerant. then see if the vac holds for 30 minutes and hour, what ever. in your case, you would have lost vac immediately. the vac removes air out of the system (bad stuff) and waiting 30 min proves you have no leaks. you need a vac gauge of course. which you need if you want to do your own work. can use it on all cars if you buy the right one.
I also have a leak detector and didn't detect anything from the compressor or rubber hoses. It all was from the passenger side around the evaporator and hard line.
#14
Re: A/c woes
Another question on this subject.... I'm assuming the pulley on the new compressor must be smaller than the original, because my adjustment is out all the way. The old compressor was more towards the center. The stock belt is 40 inches according to Rock Auto, so am I correct in thinking I need one about 38 or 39 inches?
Last edited by 80schild; 04-25-2024 at 06:44 PM.
#15
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Re: A/c woes
I bought the vac and gauges from Harbor Freight. In the beginning it would lose vacuum in about 5 minutes. After replacing the evaporator it slowed to about 20 minutes. Hopefully this new line will be the final fix.
I also have a leak detector and didn't detect anything from the compressor or rubber hoses. It all was from the passenger side around the evaporator and hard line.
I also have a leak detector and didn't detect anything from the compressor or rubber hoses. It all was from the passenger side around the evaporator and hard line.
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Car: 90 Formula / T-tops
Engine: 305 TPI
Transmission: MD8
Re: A/c woes
As far as your belt goes, figure out what compressor was on what year car, and look up the belt size for that. That is assuming all the other pulleys would have been the same size.
https://www.thirdgen.org/forums/cool...sion-here.html
Last edited by LiquidBlue; 04-27-2024 at 11:16 AM.
#18
Re: A/c woes
exactly, I pull a vacuum, then go mow the lawn or something. still the same after I come back from lunch. until you can do that, you wont' be happy with your a/c system
As far as your belt goes, figure out what compressor was on what year car, and look up the belt size for that. That is assuming all the other pulleys would have been the same size.
https://www.thirdgen.org/forums/cool...sion-here.html
As far as your belt goes, figure out what compressor was on what year car, and look up the belt size for that. That is assuming all the other pulleys would have been the same size.
https://www.thirdgen.org/forums/cool...sion-here.html
#19
Re: A/c woes
Just an update...
I got the new liquid line from Firebird Central. It is NOT the exact same shape as the original, so I had to go to Oreilly and buy a tube bender to tweak it a bit to get it to line up. Vacuumed down to -29 and it has been holding steady for about 3 hours now.
For the belt issue, I figured out my old one was just stretched, probably from when I had air in my PS pump and overworked it.
The pulley on the new Four Seasons compressor is the same diameter as the original Harrison, however it sits inward towards the firewall just enough to make the grooves in the pulley not line up with the others exactly. I shimmed out the compressor bracket with two washers on each bolt and it appears to line up properly now.
Hopefully tomorrow I can get this thing charged up finally. Fingers crossed.
I got the new liquid line from Firebird Central. It is NOT the exact same shape as the original, so I had to go to Oreilly and buy a tube bender to tweak it a bit to get it to line up. Vacuumed down to -29 and it has been holding steady for about 3 hours now.
For the belt issue, I figured out my old one was just stretched, probably from when I had air in my PS pump and overworked it.
The pulley on the new Four Seasons compressor is the same diameter as the original Harrison, however it sits inward towards the firewall just enough to make the grooves in the pulley not line up with the others exactly. I shimmed out the compressor bracket with two washers on each bolt and it appears to line up properly now.
Hopefully tomorrow I can get this thing charged up finally. Fingers crossed.
#20
Junior Member
Re: A/c woes
I'm glad to hear that your system is now holding a vacuum. Do you have a good thermometer to measure your vent temperature? Let us know how it turns out.
#21
Re: A/c woes
Okay so I charged it up today and it just gets barely cool, but not as cold as it should. I don't have a scale, but I added about 2.5 cans (12oz cans). It was 75 degrees outside when I took these pics, and going by what I've researched that high pressure side looks too high (only driver side fan running). The pressures do drop more when the aux fan turns on (passenger side), but that's erratic since it's not controlled by the a/c fan switch. I do have a lower 215 degree switch in that one at least.
The accumulator never got cold enough to start sweating, but I know the evaporator must have because water was dripping out from under the car. Also the compressor is just staying on constantly. Shouldn't it be cycling (not rapidly though)?
The accumulator never got cold enough to start sweating, but I know the evaporator must have because water was dripping out from under the car. Also the compressor is just staying on constantly. Shouldn't it be cycling (not rapidly though)?
Last edited by 80schild; Yesterday at 08:59 PM.
#22
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Car: 1983 G20 Chevy
Engine: 305 TPI
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Re: A/c woes
Pressures do not look too high to me especially for only one fan operating. System sounds low to me. I would add some more refrigerant until the liquid line after the orifice tube and the accumulator start to reach similar temperature. Once cool refrigerant is returning to the compressor the high side pressure usually falls. Go slow at this point, feel the accumulator at regular intervals for it to start getting cool and watch for the pressure drop as the system starts returning cool refrigerant to the compressor. If you have a decent amount of humidity in the air, I would not expect the system to cycle much if any at idle even on a 75F day. The pressures in the FSM are at 2,000 rpm, high blower speed, recirculate on after ~10 minutes of stable operation with doors and windows closed. Temps are center vent. What was your relative humidity when you tested that?
Last edited by Fast355; Today at 01:47 PM.
#23
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Car: 1983 G20 Chevy
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Re: A/c woes
This was after the clutch fan engaged and was pulling a massive amount of air across my condenser in the 87 G20. When the fan is freewheeling it is closer to 250-275 psi on a 75F day. On a very hot day, I have not seen any system not cycling on the ~425 psi high pressure cutout especially with a heat soaked interior. Depending on ambient temps 375-425 psi does not scare me for brief idle conditions much less 225-250 psi. The high pressure cutouts were added to the R134a systems for a reason. The mid 90s S10 even had a compressor engagement delay to allow the engine to run after a hot restart and the clutch fan to spin to cool off the tiny cramped engine bay before the compressor engaged. Higher pressures have always been an issue with R134a systems especially conversions from R12. I need to put a 12-14" pusher tied into the ac clutch circuit via a relay on my 1987. You could tie it into your OE AC fan switch. Something I would consider on your car as well.
Last edited by Fast355; Today at 02:00 PM.
#24
Junior Member
Re: A/c woes
I'm not an automotive AC pro but I do all of my own work. I really enjoy discussing and learning more about AC. I do have all of my own automotive AC tools including a vacuum pump and a Mastercool recovery machine.
What is the specified refrigerant capacity of a 3rd gen? Did the 3rd gen come with R12? My 1991 Fox Coupe was originally R12. Stated capacities for my car are meaningless because I had to make my own hoses for the LS3 swap and the hoses are much shorter than OEM Ford.
80schild, you said, "it just barely gets cool." Do you have a thermometer to actually measure the vent temperature? If so, measure with the windows up and the AC system on "max" and/or recirculate.
Fast is absolutely correct; that 225psi high side reading isn't too high at all. If it were me, I'd want both fans running pulling as much air through the condenser as possible.
What is the specified refrigerant capacity of a 3rd gen? Did the 3rd gen come with R12? My 1991 Fox Coupe was originally R12. Stated capacities for my car are meaningless because I had to make my own hoses for the LS3 swap and the hoses are much shorter than OEM Ford.
80schild, you said, "it just barely gets cool." Do you have a thermometer to actually measure the vent temperature? If so, measure with the windows up and the AC system on "max" and/or recirculate.
Fast is absolutely correct; that 225psi high side reading isn't too high at all. If it were me, I'd want both fans running pulling as much air through the condenser as possible.
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Fast355 (Today)
#25
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Car: 1983 G20 Chevy
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Re: A/c woes
I'm not an automotive AC pro but I do all of my own work. I really enjoy discussing and learning more about AC. I do have all of my own automotive AC tools including a vacuum pump and a Mastercool recovery machine.
What is the specified refrigerant capacity of a 3rd gen? Did the 3rd gen come with R12? My 1991 Fox Coupe was originally R12. Stated capacities for my car are meaningless because I had to make my own hoses for the LS3 swap and the hoses are much shorter than OEM Ford.
80schild, you said, "it just barely gets cool." Do you have a thermometer to actually measure the vent temperature? If so, measure with the windows up and the AC system on "max" and/or recirculate.
Fast is absolutely correct; that 225psi high side reading isn't too high at all. If it were me, I'd want both fans running pulling as much air through the condenser as possible.
What is the specified refrigerant capacity of a 3rd gen? Did the 3rd gen come with R12? My 1991 Fox Coupe was originally R12. Stated capacities for my car are meaningless because I had to make my own hoses for the LS3 swap and the hoses are much shorter than OEM Ford.
80schild, you said, "it just barely gets cool." Do you have a thermometer to actually measure the vent temperature? If so, measure with the windows up and the AC system on "max" and/or recirculate.
Fast is absolutely correct; that 225psi high side reading isn't too high at all. If it were me, I'd want both fans running pulling as much air through the condenser as possible.
Last edited by Fast355; Today at 02:05 PM.
#26
Junior Member
Re: A/c woes
Fast, I took another look at your chart in post #22 and I'm surprised at the vent temperatures on the far right of the chart. I would've expected them to be lower. All of my cars run cooler than what that chart is showing so maybe they're all performing, very, very well!
#27
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Re: A/c woes
Fast, I took another look at your chart in post #22 and I'm surprised at the vent temperatures on the far right of the chart. I would've expected them to be lower. All of my cars run cooler than what that chart is showing so maybe they're all performing, very, very well!
It was nearly 90F and about 65% RH the other day and I had to back off the cycling switch on the 1987 G20 system I just detailed the build of by about 1/2 turn. On a highway trip, the AC got down to 26F out of the center vents and started freezing up the evaporator core.
Last edited by Fast355; Today at 02:10 PM.
#28
Junior Member
Re: A/c woes
I don't own a 3rd gen.......yet. I've been in the IROC market since last July. I'm assuming that 3rd gens come with two, non-shrouded puller fans, right? Do 3rd gen guys tend to replace the stock fans with something more powerful? I've got a brand new, OEM C7 Corvette, PWM fan controlled by my Holley Dominator in my Fox coupe. I'm a little surprised how physically small the C7 fan is but it is a 600 watt fan that moves a lot of air Genuine, OEM GM C7 Corvette fan
The late model, 6th gen Camaro fans are monstrous at 850 watts and physically very large Genuine OEM GM 6th Gen Camaro fan
Both of these fans are made by SPAL in Italy.
The late model, 6th gen Camaro fans are monstrous at 850 watts and physically very large Genuine OEM GM 6th Gen Camaro fan
Both of these fans are made by SPAL in Italy.
#29
Junior Member
Re: A/c woes
I am too, but I can make them perform far better. On a 115F day, my 97 Express with dual evaporators will get mid to low 30s out of the vents at highway speed.
It was nearly 90F and about 65% RH the other day and I had to back off the cycling switch on the 1987 G20 system I just detailed the build of by about 1/2 turn. On a highway trip, the AC got down to 26F out of the center vents and started freezing up the evaporator core.
It was nearly 90F and about 65% RH the other day and I had to back off the cycling switch on the 1987 G20 system I just detailed the build of by about 1/2 turn. On a highway trip, the AC got down to 26F out of the center vents and started freezing up the evaporator core.
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Fast355 (Today)
#30
Re: A/c woes
Okay so I did two things today which seemed to fix the issue. I had this nagging feeling that not enough air was being pulled through the condenser. I did put foam in the gaps on the sides when I installed it, but didn't put anything at the top. I pulled off the top cover and sure enough there was a huge gap there. I put in some 1"x1" foam and even that wasn't enough, so I stuffed in some pipe insulation until the whole cavity was full. The second thing I did was to turn the screw in the low pressure switch counterclockwise 1/4 turn.
I just took it for a drive and it's nice and cold now.
I just took it for a drive and it's nice and cold now.
#31
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Car: 1983 G20 Chevy
Engine: 305 TPI
Transmission: 4L60
Axle/Gears: 14 bolt with 3.07 gears
Re: A/c woes
I don't own a 3rd gen.......yet. I've been in the IROC market since last July. I'm assuming that 3rd gens come with two, non-shrouded puller fans, right? Do 3rd gen guys tend to replace the stock fans with something more powerful? I've got a brand new, OEM C7 Corvette, PWM fan controlled by my Holley Dominator in my Fox coupe. I'm a little surprised how physically small the C7 fan is but it is a 600 watt fan that moves a lot of air Genuine, OEM GM C7 Corvette fan
The late model, 6th gen Camaro fans are monstrous at 850 watts and physically very large Genuine OEM GM 6th Gen Camaro fan
Both of these fans are made by SPAL in Italy.
The late model, 6th gen Camaro fans are monstrous at 850 watts and physically very large Genuine OEM GM 6th Gen Camaro fan
Both of these fans are made by SPAL in Italy.
I have seen many fan upgrades applied to them. If I am going electric amd have a typical GM 28 x 17" core radiator, I tend to use the Nissan fans for a NV200. Typically easier to find and same basic dimensions as the LS1 fans. The Nissan fans also use dual speed motors that are very easy to set up to be dual speed. You can use the factory dual fan wiring to enable both fans to run on low speed off the AC fan wiring and bump up to high speed when the thermostatic switch in the head comes on. The Nissan fans are very compact, fairly quiet especially on low speed and move a lot of airflow even on low speed. The dual fans on low are quieter, move more airflow and draw less amps than the single fan does when it is on. For over the past decade the V6 Altimas and Maximas also have had a near identical pair of fans. My buddy uses the NV200 aka City Express fans on all his C10 LS swaps too even with ac. New aftermarket NV200 fan setup is about $130 so cost point is very good.
#32
Re: A/c woes
The 87 LG4 car started with a single shroudless puller fan.
I have seen many fan upgrades applied to them. If I am going electric amd have a typical GM 28 x 17" core radiator, I tend to use the Nissan fans for a NV200. Typically easier to find and same basic dimensions as the LS1 fans. The Nissan fans also use dual speed motors that are very easy to set up to be dual speed. You can use the factory dual fan wiring to enable both fans to run on low speed off the AC fan wiring and bump up to high speed when the thermostatic switch in the head comes on. The Nissan fans are very compact, fairly quiet especially on low speed and move a lot of airflow even on low speed. The dual fans on low are quieter, move more airflow and draw less amps than the single fan does when it is on. For over the past decade the V6 Altimas and Maximas also have had a near identical pair of fans. My buddy uses the NV200 aka City Express fans on all his C10 LS swaps too even with ac. New aftermarket NV200 fan setup is about $130 so cost point is very good.
I have seen many fan upgrades applied to them. If I am going electric amd have a typical GM 28 x 17" core radiator, I tend to use the Nissan fans for a NV200. Typically easier to find and same basic dimensions as the LS1 fans. The Nissan fans also use dual speed motors that are very easy to set up to be dual speed. You can use the factory dual fan wiring to enable both fans to run on low speed off the AC fan wiring and bump up to high speed when the thermostatic switch in the head comes on. The Nissan fans are very compact, fairly quiet especially on low speed and move a lot of airflow even on low speed. The dual fans on low are quieter, move more airflow and draw less amps than the single fan does when it is on. For over the past decade the V6 Altimas and Maximas also have had a near identical pair of fans. My buddy uses the NV200 aka City Express fans on all his C10 LS swaps too even with ac. New aftermarket NV200 fan setup is about $130 so cost point is very good.
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Fast355 (Today)
#33
Junior Member
Re: A/c woes
80schild, awesome that you sealed up your condenser to improve the airflow through it. Maybe tweaking the low pressure switch helped as well.
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