Getting A/C going for first time on 5.3l

[chevyman70]

Okay, I am starting to get my AC parts together for my 5.3l swap. I know I need freon 134r and PAG oil (which weight?). I am using the nippodenso compressor. What do I first? Where do I add the oil, and how much freon do I need?

[Clyde65]

Its cheap enough to take what you have to a shop that specializes in AC work, have them charge it. Also did you use a trinary switch or binary? I suggest a trinary so you can protect your AC system and run electric fans when needed.

[ChevyCruizer]

What AC system, stock 70's components with new style compressor, old air, etc? That will matter for both the refrigerant capacity as well as the amount of oil.

I usually take the oil capacity and split it between the compressor and the receiver dryer/accumulator. Usually more into the compressor and cycle the compressor by hand to "work it around". Don't "work" it too much or it will squirt out of the discharge port. Also when I first start the car (after charging the system) turn the AC on and off several times. On for 3 or 4 seconds (make sure the AC clutch is engaged) then turn it off quickly for 10 seconds. Do this several times to "work" the oil through the system.

Originally Posted by chevyman70

Okay, I am starting to get my AC parts together for my 5.3l swap. I know I need freon 134r and PAG oil (which weight?). I am using the nippodenso compressor. What do I first? Where do I add the oil, and how much freon do I need?

[chevyman70]

Originally Posted by Clyde65

Its cheap enough to take what you have to a shop that specializes in AC work, have them charge it. Also did you use a trinary switch or binary? I suggest a trinary so you can protect your AC system and run electric fans when needed.

I forgot about the switch. Okay so I'll go with a trinary switch. That would be on the high side, right? Also, I currently do not have a fan. So, I would need to research all the wiring schematics for a fan.
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[chevyman70]

Originally Posted by ChevyCruizer

What AC system, stock 70's components with new style compressor, old air, etc? That will matter for both the refrigerant capacity as well as the amount of oil.

I usually take the oil capacity and split it between the compressor and the receiver dryer/accumulator. Usually more into the compressor and cycle the compressor by hand to "work it around". Don't "work" it too much or it will squirt out of the discharge port. Also when I first start the car (after charging the system) turn the AC on and off several times. On for 3 or 4 seconds (make sure the AC clutch is engaged) then turn it off quickly for 10 seconds. Do this several times to "work" the oil through the system.

Okay so I used another board member's suggestion. I am using a new evaporator from a 77 olds, acumulator from a 77 truck, nippodenso compressor, a new parallel condensor. The accumulator has a port for service and a port for a switch. I am not sure if a trinary switch would fit on it. I believe it's a 1/4 thread.
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[ChevyCruizer]

Yes, it goes on the high side. If the threads match up sure put it on the accumulator switch port.

I cant help with all of the AC parts from different cars, but it would be a good idea to back flush everything before you install it.

Another thing to remember is that some cans of refrigerant include an oil charge in them, so read the labels. I have never heard of anything bad coming from too much oil, but I figure a couple extra ounces of oil takes away that same amount of refrigerant capacity. Off the top of my head I think we usually add 5 ounces of oil into new compressors and 3 in other components. Research for yourself though.

Fans are easy. there are lots of threads on here about that.

Originally Posted by chevyman70

I forgot about the switch. Okay so I'll go with a trinary switch. That would be on the high side, right? Also, I currently do not have a fan. So, I would need to research all the wiring schematics for a fan. The accumulator has a port for service and a port for a switch. I am not sure if a trinary switch would fit on it. I believe it's a 1/4 thread.

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[chevyman70]

Okay so I installed everything, new hoses and all. Did a vacuum check using a small vacuum pump and ac gauges from harbor freight. It only pulled about 20 inches of vacuum. Once I closed all the valves, all the vacuum was lost in a matter of minutes. I checked all fittings and they are snugged. This would probably mean I have a leak, but where?
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[truckdude239]

Did you install new o rings?
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[chevyman70]

All new rings, and lightly coated them with oil.
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[truckdude239]

Then you missed something or something is not right are these all new parts are any of them used?

[chevyman70]

Originally Posted by truckdude239

Then you missed something or something is not right are these all new parts are any of them used?

Everything is new with the exception of the compressor.
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[ls1nova71]

It's going to be incredibly hard to find a leak under vacuum. You need to presurize the system and take a spray bottle of soapy water and start spraying all your connections, crimped hose ends ect. That said, I think A/C shops use nitrogen to fill the system since it doesn't retain moisture, but I have in the past used my air compressor, but it's not ideal, and you would at least need a drier in your air line to keep the moisture to a minimum. When I did it, I found my leak immediatley, it was at a welded fitting. then I vacuumed it down for a longer time than you normally would, just to make sure most of the moisture got boiled out. Hope this helps.

[chevyman70]

Originally Posted by ls1nova71

It's going to be incredibly hard to find a leak under vacuum. You need to presurize the system and take a spray bottle of soapy water and start spraying all your connections, crimped hose ends ect. That said, I think A/C shops use nitrogen to fill the system since it doesn't retain moisture, but I have in the past used my air compressor, but it's not ideal, and you would at least need a drier in your air line to keep the moisture to a minimum. When I did it, I found my leak immediatley, it was at a welded fitting. then I vacuumed it down for a longer time than you normally would, just to make sure most of the moisture got boiled out. Hope this helps.

Thanks! I'll try that. Just thinking out loud, when I placed the fitting in the hose, they didn't fit snugly, just slipped right in. I figured once the ac shop crimped them, they would tighten up. Is that how it works?
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[chevyman70]

Another thing, I can install the quick disconnect coupler on the high side. On the low side, the coupler does not fit, so I just thread the hose to the port. Would that be a problem?
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[ls1nova71]

Originally Posted by chevyman70

Thanks! I'll try that. Just thinking out loud, when I placed the fitting in the hose, they didn't fit snugly, just slipped right in. I figured once the ac shop crimped them, they would tighten up. Is that how it works?
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Usually the ends are a prety snug fit and once you put them in, you almost can't get them back out. Sounds like you didn't have the right size hoses?

Originally Posted by chevyman70

Another thing, I can install the quick disconnect coupler on the high side. On the low side, the coupler does not fit, so I just thread the hose to the port. Would that be a problem?
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Are you using R134a fittings? Your old accumulator would have R12 fitting and need an adapter.
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[truckdude239]

You need the retro fit kit with multiple size adpaters the r134 hoses should not screw on any fitting
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[chevyman70]

Originally Posted by ls1nova71

Usually the ends are a prety snug fit and once you put them in, you almost can't get them back out. Sounds like you didn't have the right size hoses?


Are you using R134a fittings? Your old accumulator would have R12 fitting and need an adapter.
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so this is what I have. The high pressure is for 134a, the low pressure is on the accumulator, its for r12 and r134a.

[truckdude239]

That one port is for the a/c pressure switch a oring goes in the groove try a low side fitting on the other fitting on the accumulator
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[chevyman70]

Originally Posted by truckdude239

That one port is for the a/c pressure switch a oring goes in the groove try a low side fitting on the other fitting on the accumulator
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I went and bought an adapter. I'll try vacuum test tomorrow again.
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[l92Firebird]

Did you do your own crimps on a/c lines or have a shop crimp them?

[chevyman70]

Originally Posted by l92Firebird

Did you do your own crimps on a/c lines or have a shop crimp them?

AC shop crimp them
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[chevyman70]

Originally Posted by ls1nova71

Usually the ends are a prety snug fit and once you put them in, you almost can't get them back out. Sounds like you didn't have the right size hoses?


Are you using R134a fittings? Your old accumulator would have R12 fitting and need an adapter.
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I called AP Air, they said that the fittings fit loosely on the hose til crimp. I haven't checked for leaks, but I am hoping its not that where's leaking.
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[chevyman70]

Originally Posted by ls1nova71

It's going to be incredibly hard to find a leak under vacuum. You need to presurize the system and take a spray bottle of soapy water and start spraying all your connections, crimped hose ends ect. That said, I think A/C shops use nitrogen to fill the system since it doesn't retain moisture, but I have in the past used my air compressor, but it's not ideal, and you would at least need a drier in your air line to keep the moisture to a minimum. When I did it, I found my leak immediatley, it was at a welded fitting. then I vacuumed it down for a longer time than you normally would, just to make sure most of the moisture got boiled out. Hope this helps.

I found where it was leaking. The high side compressor adapter is leaking. It turns out that the adapter does not perfectly align to the compressor's thread. It kinks when I tighten it up.
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[Clyde65]

http://67-72chevytrucks.com/vboard/s...d.php?t=523462

[chevyman70]

So I am extremely frustrated at this point. No mater what I do to the fitting, it LEAKS! I called several places to see if they carry them, and they all say they no longer carry them. I saw the website from transair but their fittings look like this. Any other suggestions! I am almost giving up at this point.