1. Attachments are working again! Check out this thread for more details and to report any other bugs.

A/C blowing warm air

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by Bobster8375, Apr 4, 2018.

  1. Bobster8375

    Bobster8375 New Member

    Joined:
    Apr 4, 2018
    1
    1
    0
    Location:
    Alabama
    Vehicle:
    2010 Prius
    Model:
    II
    I have a 2010 Prius II. The a/c will blow cold in the mornings and the evenings, but in the afternoon when outside temp is hotter, such as 85, it will only blow cold for a few seconds and then blow warm for 10-12 minutes. The high side reading is 150 psi, the low side is 29 psi when a/c is turned to max cool and outside temp was 68. Any ideas what is cutting out the cooking when outside temp is hot?
     
    stormgrey likes this.
  2. stormgrey

    stormgrey Junior Member

    Joined:
    May 27, 2017
    9
    2
    0
    Location:
    Birmingham, United Kingdom
    Vehicle:
    2010 Prius
    Model:
    ----UK----
    Hi I too have a 2010 Prius with exactly same problem. Cold a/c early morning when outside temperature is low say 13 degrees c but almost non existent a/c at mid day when 18 degrees c outside. My a/c guy found a leaking condenser radiator so he replaced that and regassed system but still the same problem. I also noticed the drivers side central vent is warmer than the passenger side.
    Did you fix your problem?
    Anybody got any answers or suggestions? 20180629_102537.jpeg

    Posted via the PriusChat mobile app.
     
  3. ASRDogman

    ASRDogman Senior Member

    Joined:
    May 29, 2018
    5,834
    3,136
    0
    Location:
    Florida
    Vehicle:
    2010 Prius
    Model:
    Two
    You could have a bad expansion valve or compressor.
    And if your car guy said you had a leaking condenser(not a radiator) and replaced it, and you still have
    the same problem, you DON'T pay for NON repair. How did he determine it was leaking? And not
    possibly the seals?
     
  4. stormgrey

    stormgrey Junior Member

    Joined:
    May 27, 2017
    9
    2
    0
    Location:
    Birmingham, United Kingdom
    Vehicle:
    2010 Prius
    Model:
    ----UK----
    Toyita regassed system last year. When i had bumper off to do a facelufy there was staining and attracted dirt on bottom rh triangle of condenser, i cleaned this oily dirt deposit off. This year the same area could be seen to be 'wet' and a/c was low on gas. I think it was a leak but not the cause of my erratic a/c as even recently it worked well on some days! 20180622_193920.jpeg 20171103_151519%20(1).jpeg

    Posted via the PriusChat mobile app.
     
  5. Raytheeagle

    Raytheeagle Senior Member

    Joined:
    Jul 1, 2016
    11,251
    15,474
    0
    Location:
    Bay Area, California
    Vehicle:
    2019 Prius Prime
    Model:
    Prime Plus
    Might also want to check the actuators for the blend doors if one area is cooler than another.

    Have you measured the temp coming out of other locations, like the defrost or foot vents?
     
  6. JC91006

    JC91006 Senior Member

    Joined:
    Nov 10, 2013
    16,463
    8,377
    0
    Location:
    Los Angeles, CA
    Vehicle:
    2008 Prius
    Model:
    II
    Make sure you're not running the car in ECO setting, that will reduce the AC output.
     
    Raytheeagle likes this.
  7. Mendel Leisk

    Mendel Leisk Senior Member

    Joined:
    Oct 17, 2010
    54,470
    38,103
    80
    Location:
    Greater Vancouver, British Columbia, Canada
    Vehicle:
    2010 Prius
    Model:
    Touring
    High side is low:

    upload_2018-6-30_6-45-24.png

    How does the sight glass look when it's running, lots of bubbles? Ours was like that, and lacklustre cooling. Took it into dealership, paid $150 for inspection/recharge, fine now.

    I'll attach the Repair Manual excerpt, includes the above.
     

    Attached Files:

    Prieth, stormgrey and Raytheeagle like this.
  8. Dxta

    Dxta Senior Member

    Joined:
    Nov 7, 2016
    1,932
    766
    0
    Location:
    Lagos
    Vehicle:
    2008 Prius
    Model:
    II
    You may have a clogged condenser, or the system might be over/undercharged.

    Fill up the with r134a, and see what happens. If it still persists, then you got a leak somewhere in the AC system.
     
  9. stormgrey

    stormgrey Junior Member

    Joined:
    May 27, 2017
    9
    2
    0
    Location:
    Birmingham, United Kingdom
    Vehicle:
    2010 Prius
    Model:
    ----UK----
    New Condenser and new drier has been fitted and a professional regas has been done because condenser was showing signs of leaking and gas was low. However a/c wS erratic before working fine somedays and it is still erratic after this work.
     
  10. stormgrey

    stormgrey Junior Member

    Joined:
    May 27, 2017
    9
    2
    0
    Location:
    Birmingham, United Kingdom
    Vehicle:
    2010 Prius
    Model:
    ----UK----
    Thank you for the attached info really great.
    When running there are only the ocassional bubble. When a/c isnt blowing cold the Low Pressure pipe isnt very cold at all. From the documentation it says if you turn off the a/c the fluid should foam momentarily if gas amount is correct. Mine just stops so possibly it has been overgasse? It was gassed up then when bubbles stopped an extra 100gvwas added but this was done on a very hot day in UK 30 degrees Centigrade.
     
    Mendel Leisk likes this.
  11. Raytheeagle

    Raytheeagle Senior Member

    Joined:
    Jul 1, 2016
    11,251
    15,474
    0
    Location:
    Bay Area, California
    Vehicle:
    2019 Prius Prime
    Model:
    Prime Plus
    Have you checked the cabin air filter and the function of the blend doors?
     
  12. ChapmanF

    ChapmanF Senior Member

    Joined:
    Mar 30, 2008
    23,069
    14,973
    0
    Location:
    Indiana, USA
    Vehicle:
    2010 Prius
    Model:
    IV
    That was my first thought while reading the first post ... that it works ok in moderate conditions, but in extreme conditions shuts off on the high pressure limit, until the pressure comes down again.

    But then you posted the 150 psi high side reading, which doesn't seem high enough to trip the limit. So that's curious. But were you measuring at the moment it shut off?

    Have you ever pulled codes from the ECU? Hold AUTO+RECIRC while turning the car on. Two-digit codes show up in the HVAC display where temp normally goes. I think it remembers them for a limited time; try doing this pretty quickly after it stops blowing cold in extreme temps. (If you've got anything like we've got, you should be able to try this today :eek:)

    The manual should, I believe, have some specifications about what the exact conditions should be (including fan speed and position of the car doors, and ambient temp) when doing that operation. The conditions do matter.

    I think Gen 4 may have some extra air-control doors in there that affect the flow balance between driver and passenger side (don't they call it "S flow" or something?), but Gen 3 does not.

    -Chap
     
  13. Mendel Leisk

    Mendel Leisk Senior Member

    Joined:
    Oct 17, 2010
    54,470
    38,103
    80
    Location:
    Greater Vancouver, British Columbia, Canada
    Vehicle:
    2010 Prius
    Model:
    Touring
    That actually sounds good, what I've been used to in the past with Hondas. However, I believe Toyota though says to charge until bubble disappear, and then some more. And what with the lowish high pressure reading, maybe another clue. Read through the attachment to verify.
     
  14. moocowman

    moocowman New Member

    Joined:
    Jun 24, 2018
    5
    11
    0
    Location:
    Southern California
    Vehicle:
    2011 Prius
    Model:
    III
    Charging with gauges isn't reliable. They should only be used as a diagnostic tool to see if you're in the ballpark and to see what high and low sides are doing when there's trouble. Gauges look at pressure (PSI). It's a moving target, depending on the vehicle and ambient temperature. You will never be sure if you added the right amount of refrigerant. What is constant is the WEIGHT you're supposed to put into the AC system. The sticker under the hood should call for 1.04 pounds of refrigerant. The only way to be sure you're adding the correct amount of refrigerant is to empty the refrigerant from the AC system. If you don't have a recovery machine, the only option is to vent into the atmosphere, which isn't legal. Then you have to pull a vacuum to make sure you suck out as much air as possible. The vacuum also makes it easier for the system to suck in new refrigerant. This you can do yourself if you have a vacuum pump or buy the cheap AC evacuator form Harbor Freight (you'll also need an air compressor). Then you can either add the right amount (weight) of refrigerant from the small cans OR if you're using a large keg, use a sensitive digital scale to weigh the keg as you add. I hate saying this, but this is one repair in which it's true... It's really better to just have a shop do this. And make sure the shop has a real AC machine. If they're just using gauges, they're not doing you any favors. How do I know? I owned a chain of auto shops for 15 years. In the beginning, we were guilty of being that shop that rolled the dice and charged AC systems with gauges. You can do all the other stuff on your own, checking for leaks with a UV light, replacing leaky components, etc. But leave the charging to someone who has a machine.
     
    Sue Ellen and CR94 like this.
  15. stormgrey

    stormgrey Junior Member

    Joined:
    May 27, 2017
    9
    2
    0
    Location:
    Birmingham, United Kingdom
    Vehicle:
    2010 Prius
    Model:
    ----UK----
    I changed cabin filter 6 months ago because Toyota dealers dont seem to bother, they just tick the check list. The left central vent is only 1 degree c different from the right central vent but using a digital temperature guage/probe high lights this minor difference.
    The air flow control appears to work ok as does the temperature control.
    Today when the ambient temperature was 26 degrees c the a/c worked fine producing between 6 and 9 degrees c from the vents. Puzzling how it can work fine one day and almost not at all on another day.
     
    Raytheeagle likes this.
  16. stormgrey

    stormgrey Junior Member

    Joined:
    May 27, 2017
    9
    2
    0
    Location:
    Birmingham, United Kingdom
    Vehicle:
    2010 Prius
    Model:
    ----UK----
    The pressures were from the first poster.
    Holding down the two buttons for error codes gave me 00 and nothing else which i undertand means no error codes are stored.
     
  17. ChapmanF

    ChapmanF Senior Member

    Joined:
    Mar 30, 2008
    23,069
    14,973
    0
    Location:
    Indiana, USA
    Vehicle:
    2010 Prius
    Model:
    IV
    Hmm. Looking more closely at the DTC list, there's a column showing which ones are "memorized" and what it takes to "memorize" them. For example, the 11 code for a weird reading from the cabin temperature sensor will be memorized if the reading is weird for 4 seconds or more. Most codes are memorized. Code 23 isn't memorized at all (weird pressure sensor reading), so I guess you only see that if it's weird at the moment you check. There are a few others on the list that don't get memorized.

    Might be worth connecting Techstream and watching the live data. You can actually watch the high-side pressure (it's a real pressure sensor, not just limit switches) during operation, without having to hook up a gauge set. (Pity it doesn't also have a low-side sensor!)

    -Chap
     
  18. Tamas Patai

    Tamas Patai Junior Member

    Joined:
    Feb 13, 2019
    18
    6
    0
    Location:
    Hungary
    Vehicle:
    2010 Prius
    Model:
    Active
    Strange thing happened to me this week (2010 Prius): A/C was blowing hot air until the engine reached a certain temperature. Then it's blowing cool air. Strange. Using OBD Fusion, I saw the A/C compressor won't start at all. When the coolant temp reached 91 Celsius, the radiator fans started, and the A/C compressor also started.
    I've just got replaced my head gasket in a service shop, and the problem came after it. So I called them, and they suggest to check the A/C compressor signal cable plug, because it can be filled with coolant, preventing communication and maybe worse.
    I've checked, and as you see in these pictures, it was full of gunk. I used an air compressor to dry out and voilá: A/C is cool again, it starts when I push the button!
    Be careful not to pull out the orange high voltage cable.
    Do not try - or be very careful - to use any mechanical tools to clean the pins - they are very soft, bending easily.

    I hope it helps.

    before1.jpg before2.jpg after1.jpg after2.jpg
     
    Sue Ellen and jb in NE like this.
  19. Mendel Leisk

    Mendel Leisk Senior Member

    Joined:
    Oct 17, 2010
    54,470
    38,103
    80
    Location:
    Greater Vancouver, British Columbia, Canada
    Vehicle:
    2010 Prius
    Model:
    Touring
    Spraying water in the engine bay, especially pressure washing, can leave water in that connection. It's like a little cup.
     
    Tamas Patai likes this.
  20. cookprius

    cookprius Junior Member

    Joined:
    Jan 2, 2009
    20
    4
    0
    Location:
    Texas
    Vehicle:
    2007 Prius
    Model:
    N/A
    Tamas - excellent work figuring this out after speaking with the shop! I need to check to see if there's any water/coolant/gunk in my connector (2014 Plug-in Prius). I've gotten the air filter boxes off and have access to the connector BUT cannot figure out how to unclip the plug! How did you do it?

    Thanks,
    Dan