A/C RECHARGE pull the rest of the refrigerant in?

2019 TOYOTA HIGHLANDER
4WD • AUTOMATIC
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MCSWANSON11
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I had a rock impact on my a/c condenser. I replaced the condenser. I have evacuated, vacuumed the system, and verified no leaks.i have 12 oz cans of refrigerant. Yes it is the proper refrigerant. I have both the high and low manifold ports closed and both hose to car lines open. I connect the can and open the flow. I then open ONLY the low pressure manifold and the low pressure gauge appears to equalize with the can. I cant seem to get enough refrigerant in the system to trigger the compressor to pull the rest of the refrigerant in. I believe this to be the case because the high pressure gauge is still at -30 inHg. I had the car on and A/C on full blast, recycle, etc. I also have 2 fans blowing into the front of the car. I did not take photos of the gauge after vacuum but both gauges read and held -30 inHg. Everything is completely closed currently. Gauge depicts current pressure. No air or other has entered the system.
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Aug 2, 2026 at 4:48 PM
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STEVE W.
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OK, You connect the line to the can, pierced the can, then opened only the LOW side valve on the manifold. The low side valve on the car is open as well? If yes but you are seeing no flow, close the low valve and the port valves, now try purging the manifold by opening the can valve and the manifold low side, do you get 134 at the end of the hose? If yes then reconnect the manifold. Now with the engine OFF open the high side manifold valve and port on the vehicle. Flip the can upside down. Do you see any change on the low side gauge? If yes, let it empty the can. Then close the high side, connect the next can and start the engine, see if the compressor now pulls in the gas you put in. If it does, continue charging on the low side. That system takes about 28 ounces normally so 12 oz should at least get it to kick on.
Aug 2, 2026 at 8:50 PM
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MCSWANSON11
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Thanks Steve. Yes, the low side port was open and I clearly saw some r134a move through the viewing chamber. I will try this in the morning. First verifying r134a traveling through the low side hose before following your instructions for high side introduction for the first 12 oz.
Aug 2, 2026 at 9:07 PM
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STEVE W.
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My machine charges through both sides but it uses a pump. The other thing would be to set the can in hot water to get it to generate a higher pressure, but it should show the same on both gauges if the hoses are connected and the top valves are closed If it isn't you might want to verify the gauges as well, just reverse the connections on the manifold and verify that the high side works. I've had a gauge fail before. Just be sure to switch back and close the high side valve so you are not bypassing the system through the manifold.
Aug 2, 2026 at 9:22 PM
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MCSWANSON11
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I followed your first message and am in the process of introducing the inverted can through the high side. High side pressure changed as soon as I opened the high side manifold and I saw the refrigerant moving quickly. can was empty in less than 5 minutes. Closing everything and starting the car to introduce through the low side again.
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Aug 3, 2026 at 12:33 PM
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MCSWANSON11
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Car is running. cold a/c flowing. But it does not seem to be taking refrigerant through the low side with the new can. My guess is a bad valve connected to the car port. Can I add all the refrigerant through the high side with the car off?
Aug 3, 2026 at 1:00 PM
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MCSWANSON11
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99% sure compressor kicked in but system only has ~12oz and current connected can is not getting lighter or colder. The can is opened and distributing.
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Aug 3, 2026 at 1:10 PM
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STRAILER
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Try this, remove the low side connection from the car, then with the recharge can on the manifold set, open the low side valve to see what the pressure inside the can is, this will tell us if the can is connected correctly and if there is refrigerant present.
Aug 3, 2026 at 1:24 PM
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MCSWANSON11
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This is the pressure rating. It is equal to the can pressure.
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Aug 3, 2026 at 1:30 PM
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STRAILER
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Yep, you are good. So when you open the valve with the system on and running with the low side connected what happens?
Aug 3, 2026 at 1:39 PM
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MCSWANSON11
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My apologies for the shortness. I am grateful for every message. They all help. Im a bit frustrated that this has taken me so long after replacing the condenser was not complicated. This is my 3rd day working on it after the condenser took 1/2 a day. I have confirmed refrigerant distribution for each can and the only way I have been able to add refrigerant with any success was into the high side with the car off for the first full can. Which resulted in cold a/c through the vents; but it was cyclical with parts colder than others.
Aug 3, 2026 at 1:55 PM
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MCSWANSON11
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The low side stays at that pressure pretty consistently.
Aug 3, 2026 at 1:56 PM
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MCSWANSON11
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By pretty consistently.. it only changes based on bleeding the feeder hose attached to the can.
Aug 3, 2026 at 1:58 PM
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STRAILER
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It is like the valve on the manifold set is not opening the low side AC system valve so refrigerant can flow into the system, double check that the low side manifold valve is fulling tightened onto the service valve. No worries on the frustration, we all have been there done that. Please check out this video as well.

https://www.youtube.com/watch?v=4EqdrBVb0sY

Let me know.
Aug 3, 2026 at 2:01 PM
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MCSWANSON11
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Haha funny that is one of the videos I watched a couple times. Thanks for the grace too. Everything is securely fashioned.
Aug 3, 2026 at 2:26 PM
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MCSWANSON11
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Can I really not add another can to the high side in the same way I added the first can?
Aug 3, 2026 at 2:58 PM
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STEVE W.
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The problem with using the high side is that it's VERY easy to overcharge the system. If you run it as it currently is, what are the high and low side pressures? I'm just looking to see if the system is functional. Then you could add a second can on the high side BUT only once the system stabilizes. That would put you at about 23 oz (you lose some in the hoses) that should at least get you cold air. Normally what you need to see on the gauges to be able to add is for the compressor to pull the system down to 20-30 psi with the compressor on. Then it comes down to the temperature you are working in. If you look at the attached chart for the normal pressures at given temperatures you can see what a good system would run at.
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Aug 3, 2026 at 3:35 PM
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MCSWANSON11
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Thank you. I will use that chart and cross reference what my current setup is to confirm proper function before adding more refrigerant. The system has to be working since I am getting cold air with only 12 oz of refrigerant.
Aug 3, 2026 at 4:30 PM
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MCSWANSON11
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How long should I wait for the system to settle?
Aug 3, 2026 at 4:38 PM
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MCSWANSON11
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And to answer your question.

That image is what it ws consistently running at. And it was between 70 and 75F today.
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Aug 3, 2026 at 5:29 PM
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MCSWANSON11
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Just want to close this out. I believe I have a fully charged and working a/c system again. Thanks everyone for the help!
Aug 3, 2026 at 8:27 PM
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STEVE W.
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Good to hear. Great job. Please return anytime with your automotive questions.
Aug 4, 2026 at 12:11 AM
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