AC oil quantity, and 134a quantity needed

[SBNova]

I posted this in someone elses thread and didnt get any response, so here it goes in my own thread;

After my dilema with AC compressors, I finally have my system vac'd and filled. I got a used compressor from a member here. He put plugs in the holes for shipping to keep any oil from leaking out. I removed the plugs and maybe a drop or two came out with it upside down. It didnt seem to have much in it if any. I hooked it all up and vac'd it to -30 over about 5 minutes time. I had also thoroughly flushed all the lines and changed the orifice and drier.

So when I bought freon (134a) I picked up one can of 134 w/stop leak, and a can of 2oz Esther oil w/1 oz 134a in it since I was unsure about the oil quantity.

I start the truck, with the AC on high. As I added the oil/134, the comprssor started to cycle, but very quickly. Then I added the 13(?) oz can of 134 w/ stop leak, and the compressor was running solid. If I upped the idle speed, it would shut down. So I put a washer under the idle screw which raised the idle to 1500. At this speed, I added more 134a, maybe a half 13oz can, and the compressor would just run solid, at about 25-27 psi on the low side. It seems to cut out at 25.

The problem is my vent temps are only 56-60 at best. Any less freon and the compressor doesnt run much. I didnt think (by quantity) that I put too much in. Theres 3oz of oil/134, 13oz of stop leak/134, and maybe 5oz of straight 134 for a total of 21 oz. Does this sound right?

Should I have added the oil? Is this too much or not enough oil?

Help please, its HOT in Florida!

 

[Loeryder]

Re: AC oil quantity, and 134a quantity needed

I need the same info.

MY AC has been unhooked for over a year and its time to hook it back up.
What all needs to be replaced if it has sat open?

I taped the ends of the lines closed to keep debris out but not sure if that was enough.

 

[SBNova]

Re: AC oil quantity, and 134a quantity needed

I used a normal/regular Factory Air brand orifice tube, part number 38623 from AdvanceAutoparts. They also have "optional automatic adjusting"orifice tubes. Does anyone use these? They list two different ones, one for under 105 degrees and one for over 105 degrees.


Part No.
38902 Factory Air Tube Orifice A/c Fctry
Orifice Tube; Optional Automatic Adjusting Orifice Tube for normal climates (105°-)


They also list this one;

Part No.
46011 Ready-Aire Expansion Valve & Orifice Tube
Orifice Tube: A Variable Orifice Valve Pn# {46701}, Can Be Used To Replace The Original Orifice Tube.;

Does anyone have any experience with these?

 

[Loeryder]

Re: AC oil quantity, and 134a quantity needed

Never heard of an orifice tube.
Is it necessary to replace it?

I have been told to replace the drier, but that was it.

 

[dhorsman2000]

Re: AC oil quantity, and 134a quantity needed

you need to add more 134a. You should have 2 lbs of 134A (80% of the R12 value) or 36 oz of 134. Then your compressor will probably run normal. It sounds like your low side pressures are too low? What are your high side pressures doing? First thing I would do is put in 11 more ounces of 134, that's almost a pound low, and see what happens. If your temps still aren't cool enough check to make sure your condensor isn't plugged with debris, even if it's not maybe hit it with the garden hose. I cleaned one on a 911 earlier this summer and vent temps dropped almost 20 degrees....

 

[SBNova]

Re: AC oil quantity, and 134a quantity needed

I couldnt check the high side pressures. Dummy me had an assortment ofhigh side adapters and none of them seemed tofit, so I didnt put one on figuring I could do it later. After I charged the system, I found the correct adapter, but as most of you know, requires releasing the system contents to install it. Since I had no idea what the high side was doing, and wanted to check the screen in my orifice tube, I let it all out to start over. My orifice has some debris- which suprised me as I feel I cleaned the hell out of the system. Im just debating on wether I should switch to a differnt orifice tube before I recharge the system again. The high side fitting is in place now so I'll know the high side readings in the future.

Anyone know about the oil quantity?

 

[SBNova]

Re: AC oil quantity, and 134a quantity needed

Just by shopping at the parts store, it seems that 8oz is *full* just going by what comes in some kits. There are changeover kits, from R12 to 134a, and they usually have 6oz of oil in them.

I think I'll add a little more oil, since Ive only got what was in the compressor plus 2 oz that I added.

 

[hhcs]

Re: AC oil quantity, and 134a quantity needed

My AC quit working the first yr I had my truck it cycled ok then it set through the winter and would only short cycle after that, so after 3 no AC albany trips, I decided to buy a retrofit kit from AutoZone for about $40.00, this kit had the new adapters, a low pressure gage and 3, 12 oz cans of high mileage
R-134a with 10 oz r-134a, 2 oz of high mileage lub and stop leak, I did not do anything to the system but install the adapters 0 LBS of pressure on the low side, I had to use all 3 cans and the compressor stays on at 36 LBS. on low side readings, I checked my 2004 Sunfire and it was reading 40 LBS on low side, I am going to run it for a week and then I may add a little more.

 

[shook0002]

Re: AC oil quantity, and 134a quantity needed

I used one of the changeover kits, with PAG oil. It took 3 cans and is ice cold. I also vacuumed it for about 2 hours to make sure all the air and moisture got out.