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Should air get colder with acceleration???

Discussion in 'Gen 2 Prius Technical Discussion' started by thedeerleg, Oct 30, 2010.

  1. thedeerleg

    thedeerleg New Member

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    Hello,

    I have a 2005 Prius and have a question about the air conditioning that I haven't been able to find an answer. When I'm driving on the highway, or at speeds over 50 without frequent stops the air is freezing, however, when I'm driving in the city, with a lot of red lights and stop signs the air is hardly cold at all... it seems to blow colder when I start accelerating, and will blow cold as long as I maintain acceleration. Is this normal? Surely there is a way to reset it so it will be cold when I'm idling or at red lights? Perhaps its faulty? Idk, It's nt as if it wont blow cold, thats why I'm inclined to think it is some kind of feature, I just need to know how to correct it so I don't sweat my nice person off when I'm at a redlight. (I live in Florida)

    Any info is helpful,

    Thanks very much!
     
    #1 thedeerleg, Oct 30, 2010
  2. Patrick Wong

    Patrick Wong DIY Enthusiast

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    I suggest that you make the Prius READY and set the AC temp control to MAX COLD. Then open the hood and look between the engine and the radiator to see if the radiator fans are running. You should see at least one fan in operation (out of two).

    If neither fan is running, then that is the reason why your system is not cooling when the car is at rest or at low speeds. The AC condenser needs to have a steady flow of air in order for the heat produced by the system to dissipate.
     
    #2 Patrick Wong, Oct 30, 2010
  3. BAllanJ

    BAllanJ Active Member

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    Sure seems odd to see people discussing AC this time of year in the northern hemisphere.
     
    #3 BAllanJ, Oct 30, 2010
  4. Bob Comer

    Bob Comer Active Member

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    We were over 80F here in coastal south carolina this week -- we've hardly got into fall yet...
     
    #4 Bob Comer, Oct 30, 2010
  5. richard schumacher

    richard schumacher shortbus driver

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    None Dare Call It Global Warming.
     
    #5 richard schumacher, Oct 30, 2010
  6. qbee42

    qbee42 My other car is a boat

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    We have had snow already.

    Tom
     
    #6 qbee42, Oct 30, 2010
  7. koolingit

    koolingit Member

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    If the fans are working, the next thing to check is the condenser. Shine a flashlight in through the bumper and look for dead bugs and bug parts. They could be blocking air flow. Be gentle in the removal process. Use a soft brush to get them off. Don't massage them into the condenser. The best way to get them off is to direct water through the condenser from the fan side but that's just about impossible with the prius.
     
    #7 koolingit, Oct 31, 2010
  8. JimboPalmer

    JimboPalmer Tsar of all the Rushers

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    We have been over 90 this month, and over 85 this week, although it has been 'cold' since Wednesday.

    [​IMG]
     
    #8 JimboPalmer, Oct 31, 2010
  9. BAllanJ

    BAllanJ Active Member

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    Yeah, I have seen the reports from the southernUS so I'm intellectually prepared for it, but with the frost on the pumpkin and grill blocking soon and also soon to run the extension cord out my apartment window for my block heater, it still causes me to shake my head a bit.
     
    #9 BAllanJ, Oct 31, 2010
  10. fuzzy1

    fuzzy1 Senior Member

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    Compared to you and me, OP is nearly on the Equator.
     
    #10 fuzzy1, Oct 31, 2010
  11. thedeerleg

    thedeerleg New Member

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    Ive checked both, the fans seem to be working because when its in park after I originally start it it blows cold fine. Its when I start driving, and dont accelerate much ie slower and trafficed areas it seems to shift from blowing cold air to warm air. Perhaps its an electrical misfire or somethings loose? because if it were fans or condensor issues wouldn't that be more permanent than intermittent?

    And yes for the weather posts, i live in south florida, its been in the high 80's all week, very hot indeed.
     
    #11 thedeerleg, Nov 1, 2010
  12. V8Cobrakid

    V8Cobrakid Green Handyman

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    ... is your system set to max cold when you're testing?

    there are a lot of computer controls to your automatic climate control. for instance, a light sensor on the dash detects if light is hitting the cab through the windshield. since this would warm the cab, it blows colder. when it's shaded, it blows warmer.

    since you're in a genIII, nothing is attached to your engine, so rpms should never change effectiveness. acceleration should have little cooling effect on your a/c because the fans should compensate when not moving.

    .... unless toyota isn't ever running the system at full.. then the extra little boost of air through the grill would make burst of better cooling. (although... if that were the case, you would get colder a/c at highway speeds too)... or toyota has it programmed to work better when the battery is filling... (help use up extra energy?...)

    the battery filling could possibly be a logical reason. higher voltages are being played with, as the soc raises. since the a/c system runs off of near battery voltage, it could (in theory) be getting a voltage boost?...

    have you checked the bubble gauge on your condenser lines under the hood? maybe you have little bubbles that shift on acceleration?...
     
    #12 V8Cobrakid, Nov 1, 2010
  13. koolingit

    koolingit Member

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    One more thing to check: Check to see that the fans are pulling air in from the front of the car through the condensor and radiator (not blowing air from the engine side through the radiator and condensor).

    If any work was done on the front of the car, the fan blades could have gotten mixed up -- one turns clockwise and the other turns counter clockwise. If the fan blades got mixed up, then both fans are blowing air instead of pulling air. The condensor isn't going to be able to do its job with 186 degree air (from the radiator) blowing over it.

    You say that when you originally start the car you have cold air but then the air warms up when you start driving slow. I'm thinking that when you first start the car (and the fans are blowing air from the engine side through the radiator and condensor) the condensor is able to do its job which is to shed heat to the cooler air that is blowing over it. BUT then the thermostat opens and now the fans are blowing 186 degree air from the radiator through the condensor. That's not going to work too well.

    When you get up to highway speed, you have 60 mph air blowing through the condensor and radiator (the right way) and the ac starts to work better. ...also...and I'm not sure of this: I think the fans shut off when the car gets over a certain speed allowing the air to pass through the condensor and radiator as the car moves through it.

    It's kind of a long shot but as PeeWee said, "It could happen."
     
    #13 koolingit, Nov 2, 2010
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