Charging ac in g body

[dickeymoore]

When charging a ac system in a g body that is probably very low because the compressor will not click on,how many cans of freon should be installed to get the compressor to come on and stay on fully charged?Thanks

 

[Bonnewagon]

If there is any pressure at all in the system, that is a good thing. That means it kept out the moisture which is bad for the system. No need to vacuum the system down. I have experimented with an empty system and found it took only a few ounces of freon to get the compressor to engage. The low pressure cut-off switch is usually 20- 25lbs. Below that it won't engage.

Do you have a gauge set? Filling without one is a crapshoot. The system is filled by weight and that requires an empty system to fill properly. So if the system requires twp pounds, that would be two one pound cans of freon to fill an empty system. If you have no idea what is in there to begin with then you are filling blindly until you get compressor engagement.

There are two ways to do what you need but gauges are required. First measure the system for any pressure. If very low, empty the system down to one psi. Then fill with the required amount. If decent pressure then the other way is to just fill a little at a time, checking the low side pressure as you go. I find that around 30-35 psi is the working pressure for a good system.

So if you have no gauge set, but have some pressure, I would empty it, then fill by can weight to the specs needed. If you go over or under by a little, no big deal. But you do NOT want to overcharge grossly and damage the compressor.

Don't let anyone see you emptying the system to atmosphere as that is illegal.

 

[dickeymoore]

So I have 14oz cans of freon,so 2 cans will be 28 ounces with another 4 ounces of freon?

 

[Ribbedroof]

Most OE Gbody systems are 3.25 pounds for an R4 compressor 3.5 pounds for an A6 compressor. The absolute best method would be to evacuate the system and recharge on a commercial AC service machine. As mentioned above just dumping random amounts of a can of refrigerant in is a crapshoot at best. Pressures will also vary depending upon the refrigerant used. Actual R 12 is somewhat difficult to get a hold of these days.There are so-called drop in replacement that are a witch’s brew of various gases. A properly converted AC system functions fine with R1 34A if our 12 is not available. There should be a label on your AC box telling you the original system capacity. In my personal experience I have found when converting to R1 34A that a good starting point is about 85% of the original charge amount

 

[Ribbedroof]

Just as a footnote I believe the fine for releasing refrigerant into the atmosphere is $25,000 per occurrence

 

[69hurstolds]

Here's a funny tidbit: Go and release a can of 152a into the atmosphere and the EPA will lose its mind. Now, got get a can of "DustOff" computer keyboard cleaner, or most any of those canned "air" containers. You can buy that all day long and it is DESIGNED to be sprayed all over your computer junk to clean the dust out of it. In fact, go to the EPA offices and start to clean their computer keyboards with it and they probably won't care. Guess what? 152a is the likely propellant in those air cans (they also use 134a among a few others, imagine that, and again, they'd have a cow over dumping a can of 134a into the air). It's not really air you're spraying, it's refrigerant. So someone please square that for me.

So nobody will ever convince me that the refrigerant game is nothing more than a cash grab.

3.25 lbs of R12 is the recommended charge for G-body factory A/C systems. AKA 52 ounces. You will need 3 full 14 oz cans of R12 and 10 ounces from another. By the time you waste some by purging lines and hooking them up, more than likely you'll eat the full 4 cans of the 14 oz ones, or you'll need 5 cans of the 12 oz ones as you'll use 4 and 1/3 cans.

 

[oldsofb]

152a is the likely propellant in those air cans (they also use 134a among a few others, imagine that, and again, they'd have a cow over dumping a can of 134a into the air). It's not really air you're spraying, it's refrigerant. So someone please square that for me.

Any time someone breaks one of those dusters out I turn it upside down and spray a frost circle on the desk to show them.

And agreed.....Cash Grab!

Hutch

 

[Wageslave]

And I thought it was nuts when my cobbled together AC system seemed happiest with 54 oz. I guess it wasn't that far off of the stock size after all.

 

[Malibu795]

Just as a footnote I believe the fine for releasing refrigerant into the atmosphere is $25,000 per occurrence

🫣🤣

I got in a pissing match getting my 308/309 licenses 🤣

Gues it's 608/609 now 🙄 HVAC/MVAC


To the OP IMO.. recommended weight charge is a good starting point.. also pull up a temp pressure chart for the refrigerant your using.. I find the system works substantially better that way.

This is the chart I use the most

 

[Bonnewagon]

so-called drop in replacement

Most of those are banned now too. In fact any R-12 advertised as a replacement is banned. The only one that is OK is Enviro-Safe. But they advertise it as an R-134a replacement. Formerly it was an R-12/ R-134 replacement years ago. I think it is propane based so some worry about it exploding. I figure if your engine compartment is on fire that bad, you have worse things to worry about. I have been using it for years as it is compatible with the OEM mineral oil our cars came with. No flushing needed. My Bonnewagon AC system is all of 45 years old, has only a used rebuilt compressor changed, and blows 30° below ambient. Not too shabby.

What gets me is, you can't evacuate a system on purpose into the atmosphere. But if your system slowly leaks all out and gets recharged every year, that is fine. I am 609 certified too, and no one could answer that for me.