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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.
Did you convert to r134? If you would, attach a picture of the high side fitting.
yeah it was converted. I took the line back to the a/c shop this morning. They are going to fabricate me a new line that won't need a shrader adapter, but it's going to have a rubber section and not be totally aluminum like the original. It won't be able to mount to the body like the original, but that'll be okay I guess.
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.
dang I didn't even know one was available! I've never looked at Firebird Central. I looked nearly everywhere else though.
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; Apr 23, 2024 at 07:36 PM.
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.
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.
Well, the shop called and said the new line was ready, so I drove an hour back there and it turns out they called the wrong person. They hadn't touched it yet, so I got it back. I just ordered the one from Firebird Central.
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 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.
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; Apr 25, 2024 at 06:44 PM.
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.
You shouldn't lose vacuum at all let alone after 20m. There's a leak still somewhere. When I built mine all out, I pulled a vacuum and it didn't decay at all when I came back to it after two weeks.
You shouldn't lose vacuum at all let alone after 20m. There's a leak still somewhere. When I built mine all out, I pulled a vacuum and it didn't decay at all when I came back to it after two weeks.
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.
You shouldn't lose vacuum at all let alone after 20m. There's a leak still somewhere. When I built mine all out, I pulled a vacuum and it didn't decay at all when I came back to it after two weeks.
yeah it was in the liquid line. I have a new reproduction one ordered from Firebird Central.
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.
My old compressor was the factory Harrison one. The new one is a Four Seasons from Rock Auto. There's no way to look up a belt size for an aftermarket compressor that I know of, especially since the same unit is used for both v-belt and serpentine setups (mine is V-belt). I'm just going to take it to Napa and see if they can give me one that's an inch or two shorter.
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'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.
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)?
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?
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.
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.
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.
Given the stock fans do not have a shroud, I would want the largest pusher fan I could put in front of the condenser. My 99 Tahoe has a PCM controlled factory pusher fan that turns on when the ac is activated under ~50 mph. These F-cars have loads of space to add one and it will force more air across the condenser than both stock fans being activated. LS1 fan assembly worked wonders too with both fans running when I TPI swapped a former LG4 1987 Transam.
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!
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!
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.
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
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.
26F? Heck, even mid 30's is "brain freeze" temperature!
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 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 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.
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 own a NV200 myself, and I can vouch that those fans are pretty powerful for that little 2.0 liter engine. Unfortunately the evaporator inside is tiny.
This was sitting at idle the other day after the interior had cooled down. On a humid day it blows dense fog out of the vents.
I can remember my step-grandfather buying a new '91 Nissan Hardbody pickup, and it would make a fog like that, it was like opening a freezer door. I've never seen another vehicle do that.
I can remember my step-grandfather buying a new '91 Nissan Hardbody pickup, and it would make a fog like that, it was like opening a freezer door. I've never seen another vehicle do that.
I tried adjusting the cycling switch and it is dead. I re-used the OE one on it because they typically do not go bad on this era of vehicle. The slightest rotation of the screw now either kills the compressor entirely or runs it all the time. Ordered a replacement unit calibrated for R143a. Should cure the evaporator freezeups as they are close to what is needed cutout wise out of the box.
Ahh. great idea. I will do that. I'll hit them up. If you dont mind me asking, did you get the part yet? How does it look? Worth the money? Fit and finish ok?
Ahh. great idea. I will do that. I'll hit them up. If you dont mind me asking, did you get the part yet? How does it look? Worth the money? Fit and finish ok?
It's been on the car for a couple of months now. It works great, but I did have to get a tube bender from the parts store and tweak it just a bit to make it line up with the connections. I also changed my condenser and evaporator, so those connections were off just a bit from the factory ones.
Make sure to use the green o-rings, and a little Nylog Blue on them doesn't hurt either.
