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AC issues with my 05 Prius Gen II

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by m0fugga, Jul 7, 2012.

  1. m0fugga

    m0fugga Junior Member

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    Hey everyone,

    My wife has recently been complaining that the AC will work for a while, but then it stops working after running for about 30 minutes. She also reports that, at that time, the air flow (blower speed?) seems to drop tremendously. I have observed the former but not the latter, so I can't say for sure that if it really drops in air flow or if it's just a matter of perception. I put my AC gauges on it and it reports the following:

    Static reading is 70/100 PSI
    Reading system on is 17/145 PSI
    Ambient temperature is ~92 degrees humidity is 65%
    Vent reading is ~77 degrees

    I'm kind of new to reading AC gauges so any tips would be appreciated.

    I can see movement in the sight glass while the vehicle is running. I'd like to add a little refrigerant (if that's what it looks like it needs) just to see if we can make it through the summer. Prior to the AC problems popping up, my wife and I were discussing trading the 05 in for a new Prius and I don't really want to drop a ton of money into it if we are just going to trade it in. What does it sound like it needs?

    Thanks in advance!
     
    #1 m0fugga, Jul 7, 2012
  2. m0fugga

    m0fugga Junior Member

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    Is anyone on that is a little more on the technical side that can help me with this?
     
    #2 m0fugga, Jul 7, 2012
  3. Patrick Wong

    Patrick Wong DIY Enthusiast

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    The refrigerant charge is low, confirmed by your gauge readings as well as your being able to see fluid motion in the sight glass. The spec is 0.2 MPa on the low pressure side and 1.47 MPa on the high pressure side (you can convert from psi to MPa by multiplying your readings by 0.006895.)

    It may be that the intermittent operation is caused by water vapor in the system. The water vapor freezes at the expansion valve orifice which stops the refrigeration process. Once the moisture melts then the system will operate temporarily. The cure requires fixing whatever leak may be present, replacing the cooler drier, evacuating the system, and recharging with the correct amount of new refrigerant.
     
    #3 Patrick Wong, Jul 7, 2012
  4. m0fugga

    m0fugga Junior Member

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    Ok, thanks for the response Patrick. I was thinking about taking it to the dealership/indie mech and having it evacuated and recharged. I thought about putting some refrigerant in it myself but everything I read said you should get a vacuum going on it which, of course, requires an air machine. Also, what I researched recommended using a scale to measure the amount of refrigerant going in, which I don't have. I'm guessing they'll check the cooler drier before they do the recharge?

    My main reason for pulling my own readings and getting some advise online was to be able to work as closely with my mechanic as possible. I don't want them telling me I need a new compressor or something when I really don't.

    Thanks again for the response; very helpful!
     
    #4 m0fugga, Jul 8, 2012
  5. Ct. Ken V

    Ct. Ken V Active Member

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    mOfugga,

    Don't forget to tell your mechanic that your A/C system needs the special Toyota compressor lubricant/oil due to the compressor being electric rather than belt driven. I don't know if there are any other "special" procedures to be followed during the evacuation/recharge.
     
    #5 Ct. Ken V, Jul 8, 2012
  6. m0fugga

    m0fugga Junior Member

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    I went ahead and took it to the Toyota dealer for evac and recharge: $180. Seems on the high side but hopefully the premium ensures I don't have to worry about them not knowing what they are doing. They put dye in it, which seems to be SOP but I've heard good things and bad things about that. What are the chances that it's not leaking and that I just needed a recharge? Seems kind of low since the system is a sealed system meaning the refrigerant must be going somewhere...
     
    #6 m0fugga, Jul 10, 2012
  7. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Sounds like the leak still needs to be identified; hence the use of dye. If your system needed a recharge then a leak exists.
     
    #7 Patrick Wong, Jul 11, 2012
  8. lech auto air conditionin

    lech auto air conditionin Senior Member

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    for a 92 degree day 17/92 sounds low for sure. There must be a leak but it not always possible to find it the first time. It dose use a special oil but none is needed if none was removed or lost. If you have the dryer sock replaced the oil will need to be added. recovering the refrigerant , vacuum , weight of the refrigerant needs to be vary close to perfect. $180.00 is a ok price the labor rate must be low there. Flat rate or book time is 1.4 hr. the ND-11 oil for the electric is about $50+ a oz (28 ml). Dye added to the a/c is good as long it is the right dye and made for electric compressors this is the important part. Then dye itself is about another $12 to $18. The refrigerant almost a 1 lb. or (490g) will be another $21-$30, no you are not going to get at the same price as in a auto parts store between $14-$19 a 12oz can R134a a repair shop can't stay in business giving away part at near cost.

    Its sounds like it should make it through the summer , and you should love your new pruis. I'm waiting for my girls new Pruis C this month.
     
    #8 lech auto air conditionin, Jul 17, 2012
  9. m0fugga

    m0fugga Junior Member

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    Well, it's been almost a year since I posted this and just wanted to report that the AC is still working like a champ. I suppose there could still be a leak, but perhaps it's such a slow leak that it'll hold a charge for a while before needing a re-up. YMMV but all-in-all a good investment of $180. Thanks for all who responded.
     
    #9 m0fugga, May 27, 2013
  10. boppo

    boppo Active Member

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    Thanks for your speedy reply. :)
    Glad it's fixed
     
    #10 boppo, May 27, 2013
  11. Britprius

    Britprius Senior Member

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    I had a similar problem about a year ago with the AC in my 2008 Prius. Topped it up from a 134a freezer can according to the Prius manual, and worked fine since.

    John (Britprius)
     
    #11 Britprius, May 27, 2013
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