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

2019 TOYOTA HIGHLANDER

4WD • AUTOMATIC

MCSWANSON11

MEMBER
20 POSTS

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

STEVE W.

✓ASE Certified Mechanic
15,205 POSTS

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

MCSWANSON11

MEMBER
20 POSTS

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

STEVE W.

✓ASE Certified Mechanic
15,205 POSTS

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

MCSWANSON11

MEMBER
20 POSTS

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

MCSWANSON11

MEMBER
20 POSTS

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

MCSWANSON11

MEMBER
20 POSTS

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

STRAILER

✓ASE Certified Mechanic
54,928 POSTS

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

MCSWANSON11

MEMBER
20 POSTS

This is the pressure rating. It is equal to the can pressure.

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Aug 3, 2026 at 1:30 PM

STRAILER

✓ASE Certified Mechanic
54,928 POSTS

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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