2oz oil charge not being sucked into AC low side

sh00ter

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Long story I may share later in a new thread on this AC compressor journey, but in short, had a completely dry system and compressor was out of oil. Filled it up manually, found the leak and fixed it, pulled vacuum for an hour, then charged system w/ 134a using the gauges. It was difficult to get the refrigerant in and took awhile, but I did get 2 cans in finally. However, I wanted to add a bit more oil after the system was closed so I got an oil charge can.

These are all the new style self sealing cans. I have 3 different can adapters that have the piecing heads, and a separate adapter that says it is supposed to be for using those with the new style can. However, no matter which adapter or combo of them I used, I just could not get much if any of the 3oz (2oz oil, 1oz 134a) can into the system.

With the 12oz 134a cans, it was difficult, but I was able to do it just using one of the traditional can taps hooked to the yellow line on the gauges. I DID NOT need to use the can adapter I mentioned before.

The process I used was hooked gauges up to high & low. Kept high open at line & closed on gauges. Kept low the same initially, hooked can up to yellow line, used purge valve on gauges to try and purge the air but on the oil charge, not much came out but it did sound like air and there was no visual oil or refrigerant in the site glass on the gauges. Then I opened up the low side on the gauges (with AC running) to try and such the oil in. Several times in trying different options, I had to close the low and try another can adapter combo on the oil charge can. Each time I purged before opening low side back up and each time there was a bit of air but no visible oil. However, I did have a decent amount of oil drip out of the line each time I unhooked to try another can adapter. So the can was not empty when I finally gave up and I convinced that maybe "some" of the oil got into the system, but the rest dripped out of the line.

I even unhooked the gauges and tried one of those cheap short low-side only charge lines with several of the same can taps and had the same result.

What is the right way to have done this and is this just a bummer of these new style, self-sealing cans?

ALSO, what the the process (unrelated) when using AC gauges...I opened the high-side at the gauges after I removed them and it scared me by purging all the pressure in the line and spewing oil all over. I guess as part of the process of using the gauges you have to purge the lines after each use once they are removed from the car?
 
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tyromeo55

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Why do you think your system is out of oil? There are few reasons to add oil. Even a lot of new compressors are pre-charged with it. Adding too much is not good for a couple of reasons and there is ZERO benefit.

The best practice for adding refrigerant (and really the only correct way in a vehicle) is to pull a good vacuum and add by weight.

Have not needed to mess with self sealing cans yet. I have a 30# jug or I use a tool that pierces the side of the can.



My gauges have a valve at the vehicle port. You can also get a little lead to add to a hose with a ball valve close to the end.



Car running..... Close valve on Hi side port at the vehicle tap, (with yellow bottle hose capped, to the bottle or valve body) crack hi and low valves on your gauges to that they can equalize. Remove low side from vehicle. Kill engine (or A/C) wait for a moment, Disconnect Hi side from vehicle.
 

sh00ter

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I had a system leak with visible leaking oil on the hose. I let it go until the compressor got hot and noisy. I removed the compressor as the system was empty by then of refrigerant and opened up the compressor and no oil came out. I filled the compressor with what I believe to be the correct amount of oil assuming the entire system was dry since the compressor was. Then I reassembled, with the leak fixed and pulled a vacuum to remove the moisture. Then I re-charged the system with the correct amount of refrigerant and the compressor was still noisy, but it was cooling good again. I decided that maybe I needed to add a little more oil just to be sure so i was trying to add it with the charge can using my gauges.

I got a new compressor and the other stuff that should be replaced, but this is my beater and as long as it is still cooling, I am going to run the hurt compressor for awhile and save the new parts for now.
 

tyromeo55

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Without seeing or touching the vehicle I can only express my thoughts. These thoughts are typed hastily so hopefully they make some sense.


Most people have no idea the ins and outs of these systems. They know a little and assume the rest. This is also true for a lot (not all) of resi HVAC techs and the internet is full of armchair warriors. Auto shops do a couple tests, replace a list of parts and then let a machine do the rest. This is good because at the end of the day they repaired the problem and the customer does not return unhappy. the only issue is that it can be expensive.

QUOTE=sh00ter I had a system leak with visible leaking oil on the hose. I let it go until the compressor got hot and noisy. Without seeing it I cant say for certain but (on modern systems) a little leaked oil often looks like a ton. It is super thin stuff. Once inside the system It is really hard to remove even if you are trying. It also collects all over the system like in the drier and coils. I bet it was still ok. The oil is circulated inside the freon. If you were running it while it was low then you were also starving the compressor for oil. for that reason some MFG's put low pressure switches on the suction line to interrupt the compressor if it gets really low but that is not the majority. I removed the compressor as the system was empty by then of refrigerant and opened up the compressor and no oil came out. That does not mean the system is out of oil I filled the compressor with what I believe to be the correct amount of oil assuming the entire system was dry since the compressor was. Unless replacing the compressor and drier I never add oil. and I make sure that the new compressor is not pre-charged. A buddy double charged his ranch wagon and it would never run right. the more room you occupy with oil the less room there is for freon. The only fix was replacing the compressor and drier to start over. Sad. It was a completely brand new system. Then I reassembled, with the leak fixed and pulled a vacuum to remove the moisture this is also done to remove non condensable gases =) .. Then I re-charged the system with the correct amount of refrigerant and the compressor By weight? was still noisy, IF it has a lot of miles on it and you ran it low on freon for a while then that might be why it is noisy. If IT cools good anbd you can tolerate the sound I would leave it alone but it was cooling good again. I decided that maybe I needed to add a little more oil just to be sure so i was trying to add it with the charge can using my gauges. Aside from adding oil it sounds like you did ok to me (maybe I would of added .5 to 1 oz but that is it) That drier probably needs to be replaced but not until you get a new compressor. Also next time you open one up go ahead and look at the orifice and screen. make sure there is no debris

Bonus, Make sure you match oil types. Not all oils play well with others even if they are the same chemistry. (like mineral oil. there is water soluble type and non) POE oil can be mixed with pag (as far as Im concerned) but it is VERY water hungry so don't add it to an open system until you are ready to vac and charge immediately after

I got a new compressor and the other stuff that should be replaced, but this is my beater and as long as it is still cooling, I am going to run the hurt compressor for awhile and save the new parts for now. That is probably what I would do also.
 
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