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heating blows cold air

Discussion in 'Gen 3 Prius Main Forum' started by memento84, Oct 28, 2017.

  1. Sam Spade

    Sam Spade Senior Member

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    NO more likely it means that the system still has air in it and the coolant isn't circulating well.
    If you paid someone to install that pump, then visit them again to finish the job.
     
  2. memento84

    memento84 Junior Member

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    that is my guess, sediment and bubbles - but it does not look like an easy access to those hoses going into firewall, unfortunately. any tricks here ?
     
  3. David Beale

    David Beale Senior Member

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    Yes, there are tricks which, unfortunately I don't know, to "bleed" the coolant system. Perhaps someone who changes their own antifreeze will post the hidden secrets. ;) My understanding is the "bubble" is in the engine compartment (air rises in coolant and that is the highest point). The bubble is drawn into the pump which then fails to pump, until it is turned off and the coolant flows back "down" to it. That causes the "gurgling" sound.

    I don't think you have to worry about "sediment". I've never seen any indication of it - the system stays pretty clean. The coolant just degrades over time (the anti-corrosion additives are used up).
     
    #23 David Beale, Oct 30, 2017
    Last edited: Oct 30, 2017
  4. memento1984

    memento1984 Junior Member

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    so I jacked up the front of the car, opened cap on the reservoir and ran the car ~1.5h. Clearly could hear the gurgling sound when I was turning blower off and cycling max/off. Tried to put gas pedal down couple times too. Clearly had some signs of foamy coolant rising. Localized two hoses, one comes in on "top" when the other one is "bottom". Top one was really hot (I think it is IN), bottom one was cooler, could hold it although really warm. will disconnect one and pour coolant in.
     
  5. memento84

    memento84 Junior Member

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    heater core was plugged. there was no fluid flow initially. now there is flow, but was affraid to go higher than 80psi blow. When reconnected now I have really nice warm air coming from driver side, but nothing in 3 others.

    is there some flap/motor/air blender that could have gone stuck so that 3 other outlets give no hot air ? even when I completely shut the one warm closed, there is no heat coming from the other ones. any ideas ?
     
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  6. bisco

    bisco cookie crumbler

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    there are vent flaps that move when you change air direction. idk how they are set up. i would assume windshield/face/floor, not right and left.
     
  7. memento84

    memento84 Junior Member

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    so the "directions" are fine, I can change windshield / floor / face without problems - but only 1, drivers side, is blowing hot air. I thought that there is one large "pipe" that blows air via heat core and then the same air is split into 4 channels (face).
     
  8. BZzap!

    BZzap! Senior Member

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    If it were me, I would start looking for rodent nesting materials in the heater ducting. You can start by removing the cabin air filter behind the glove box. If you have a rodent problem it will be quite evident. This is pretty common.
     
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  9. bisco

    bisco cookie crumbler

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    are you getting no air from the other vents, or cold air?
     
  10. ChapmanF

    ChapmanF Senior Member

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    The heater core is located quite close to where those separate channels split off, and it is built (at least the Gen 2 that I'm looking at in the New Car Features manual) with an inlet tank and outlet tank connected by many parallel water passages (as opposed to some zigzaggy finned tube where water would have to follow the entire path). So, if there's some nonuniformity of the water flow across the width of the heater core, there would not be much air travel space to mix and average out the temperature before the air feeds into the separate outlets.

    What year is this car? Your profile says 2007, but is this a different one, since you've posted under Gen 3?

    I'm stunned that you found the core to be plugged. Any sign of what it was plugged with? Has the coolant ever been changed?

    -Chap
     
  11. Boston2008Gen2

    Boston2008Gen2 Junior Member

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    I have same issue. Getting hot air in driver side but cool air on other vent. I recently changed coolant . Do you have any fix?
     
  12. 2010moneypit?

    2010moneypit? Active Member

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    Sounds like you have air in the system. Like another poster said on here. What I would do is see if you could Park at a steep incline with a hood in the uphill direction open the cooling system and see if you can get the air out. You must be careful do not open the cooling system when hot. You also need to use a scanner to monitor the temperature so you do not overheat the vehicle.
     
  13. ChapmanF

    ChapmanF Senior Member

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    On the procedure for filling and clearing of air—gen 3 moved from the coolant-recovery bottle used in Gen 1 and Gen 2 to using a "degas" bottle as the cool kids are now doing. Instead of being a backwater, the bottle has coolant circulate through it, and is designed with enough air space at the top that you no longer "open the cooling system" for letting air out.

    The hoses colored blue here are the ones that carry coolant and bubbles from high points in the system (top radiator corner, and nipple on the top of the cylinder head water outlet pipe) back to the top of the bottle:

    [​IMG]

    The repair manual procedure is to fill the bottle all the way to the "B" mark (a special mark above "F" that is only used for this procedure), close the pressure cap normally, and idle the engine up to full operating temperature and at least seven minutes longer. Let it all cool all the way down, so the coolant contracts to its normal volume at ambient temperature and pressure, and you should see that it went from the B mark down to F. It traded places with the air in the system. The air is in the bottle, where it belongs.
     
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  14. 2010moneypit?

    2010moneypit? Active Member

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    Way better than what I said.
     
  15. BZzap!

    BZzap! Senior Member

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    In other words, air in the system is displaced by coolant and is captured in the pressurized coolant resevoir, thus being a self purging system?
     
  16. 2010moneypit?

    2010moneypit? Active Member

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    In theory but does not always.
     
  17. ChapmanF

    ChapmanF Senior Member

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    That's what it does as long as you give it the right starting conditions with the right procedure.
     
  18. Boston2008Gen2

    Boston2008Gen2 Junior Member

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    Okay - My driveway is steep enough and may be i can put a Ramp as well. This will make a steep incline. Now, I should just open the cooling system (Reservoir cap ?), do i start the engine as well? Where is the air pocket, may be i can squeeze tube - I just don't know where to squeeze.
     
  19. ChapmanF

    ChapmanF Senior Member

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    I've been starting to wonder if the whole "you've got an air pocket" story gets reached for more often than it deserves, certainly for Gen 3 and later.

    Really, I've never done any spin around three times, click your heels and face uphill, leave the cap off stuff, anything beyond just doing the refilling steps in the repair manual in order as directed, and I haven't seen them not work as designed.

    Don't forget, when you look at the diagram in #33, the path for air leaving the system through the (blue highlighted) hoses runs back toward the top of the plastic bottle.

    If you put your car on too steep an upward incline, you'll be asking bubbles to go downhill to follow that path.
     
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