There are many places in the system that can leak. There are O-rings in each connection, the lines, the evaporator, the condenser, the seals on the compressor and even the ports you use to check the pressures with. All of them can be the cause of leaks. Finding the leaks is 90 percent of the issue in servicing the systems because some leaks can be very small. In your case though it should be rather easy to find unless it is the evaporator core in the dash, which is a common leak on Nissans.
Check over this guide and see if you can find the leak:
https://www.2carpros.com/articles/air-conditioner-leak-detection
I tend to use a couple methods to find leaks, one is on systems with large leaks, I will use common shop air to pressurize the system then use the soapy water method and spray down everything I can get to. The core in the dash won't be tested this way, but if there are no leaks anywhere else then I get out a second tester which listens for high pressure leaks. With that you can snake the microphone into the bottom duct and listen.
If it's a small leak, which yours isn't, I use a sniffer to check all the connections and in the ducts looking for the leaks. Some parts stores have them as loaner tools.
Once the leak is found I repair the problem and then pull a full vacuum on the vehicle and let it set for as long as possible to be sure it's sealed and any moisture is pulled out. Then it's a recharge with oil and R134A by weight.
Saturday, June 26th, 2021 AT 4:28 PM
