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0 High and Low side AC pressure

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by Richard Bjerke, Jul 16, 2022.

  1. Richard Bjerke

    Richard Bjerke Junior Member

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    I purchased a new set of gauges to use on my 2009 Prius that had stopped cooling. When I connected the gauges, both High and Low side ports showed 0 pressure. I tried to add refrigerant but it would not take any. When I removed my gauges, I saw a little green on both ports. Maybe it did take some in. Perhaps the gauges are bad. So I borrowed a proven gauge set my friend used on his Hybrid car. He got 0 pressure with his gauges also.

    Now I believe my new gauges are good and my AC system has no pressure. But what does no pressure mean? A real bad leak? I was not able to find any leak under the hood. If I have a leak, it would be the Evaporator!!!! Or could a shot Compressor be the problem? I have never gotten no pressure at all with my truck and other cars. Can anyone suggest what to do?
     
    #1 Richard Bjerke, Jul 16, 2022
  2. PriusCamper

    PriusCamper Senior Member

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    It's a variable pressure system and the amount of refrigerant it needs is measured by weight not pressure after it's been evacuated into a machine that can make that measurement precisely. The only DIY way to service it would be to weigh the container the refrigerant and lubricant come in and put it into a completely empty system. If you want to learn more about it read @lech auto air conditionin posts on here. He goes into great detail often.
     
    #2 PriusCamper, Jul 16, 2022
    lech auto air conditionin likes this.
  3. dolj

    dolj Senior Member

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    Yes, it means a significant leak. Before leaping to the worst-case scenario, you should change the valves on both the high and low service ports. If those are leaking, they will not show up on a leak test. Once you have changed those valves, pull the system down into a vacuum and to see if the system has any leaks.
     
    #3 dolj, Jul 16, 2022
  4. Frontporch

    Frontporch Member

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    I believe if you try to add refrigerant it would go from a high pressure can and leak out of a damaged ac system. You add to the low side so the pressure differential is greater. Low side you said was zero. Can must be well over 50 psi
     
    #4 Frontporch, Jul 17, 2022
  5. Richard Bjerke

    Richard Bjerke Junior Member

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    I did expect the pressure to rise a little when I added refrigerant to the low side and then go back to 0 when I turned the can off. But the pressure never moved and there was green refrigerant on each port. Ok, I will replace both ports. What other small parts should I replace while I have the system open? The condenser does not show any damage or leaks, should I replace it? How can I tell if the compressor is bad? I don't hear it running, but I am 78 and I don't hear lots of things these days.
     
    #5 Richard Bjerke, Jul 17, 2022
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