Radiator coolant not heating up or under pressure

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by DirkG, Oct 29, 2010.

  1. DirkG

    DirkG Junior Member

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    My 2007 has 160k miles and at just over 100k I had toyota change all the fluids. That was about 3 or 4 months ago, its a taxi. I started noticing the heat was only hot above 83, and some times not even hot at high. I thought I was out of fluid so I added to the overflow not wanting to open the cap on a hot motor. It didnt take much, but made the heat come back on above 80 degrees so I did nothing else.
    Last night I had no heat again after driving about 200 miles. The heat came back after turning it off for a few minutes, but I stopped at a gas station anyway when I got off the freeway.
    The overflow was full. It was also cold. So were the radiator hoses, but not what looked like power steering hoses next to it. Were those the inverter lines?
    I check that belt pullie was spinning when the engine was running, it was. It a new belt put on by dealer.
    The car doesnt show any signs of overheating, and is driven 300 or more miles a day in town and freeway. The motor was of course hot, but not overly so. None of the connected components were hot like I would expect if was overheating.
    This is something I really need to fix myself due to money shortages. Sounds like a thermostat or waterpump in a standard car, but what about in a Prius?
    Thanks
    David


    edit: I should add that when the radiator cap is off, the heat on, and the engine running, there is no movement in the antifreeze, which is full to the top of the neck but has no pressure.
     
    #1 DirkG, Oct 29, 2010
  2. DirkG

    DirkG Junior Member

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    Lots of failing inverter pump threads. Maybe while I am fixing the ICE problem, I should put a new inverter pump on also.
     
    #2 DirkG, Oct 29, 2010
  3. donee

    donee New Member

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    Hi DirkG,

    This sounds more like a problem with the dealarship not bleeding the engine, heater core and CHS (Coolant Heat Recovery) system properly. Its especially tricky in the Gen II Prius.
     
    #3 donee, Oct 29, 2010
  4. Hal W

    Hal W New Member

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    Sounds like the thermostat is stuck open? H
     
    #4 Hal W, Oct 29, 2010
  5. ccdisce

    ccdisce Active Member

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    Serpentine belt under tension?
    Impeller could be loose on the WP shaft.
    Colapsed hose?
     
    #5 ccdisce, Oct 29, 2010
  6. Joe 26

    Joe 26 Member

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    You have 3 basic possibilities

    1) Shop that changed the engine coolant did not bleed the system fully.

    2)The engine thermostat is stuck open

    3) There is some type of coolant leak or coolant loss. Since you say the reservoir is full, I wouldn't suspect this.

    First, try putting the heater on economy, full blower and max hot. Run the vehicle down the highway for 15-20 min. and see if your engine coolant reservoir gets lower. Using the max heat setting is very important.

    If that doesnt fix it, scan the engine after a good ride and check to see the engine coolant temp is normal 180-200*F. If it doesnt get there on a cool day or takes a long time to warm up, I would suspect the thermostat. Part is not expensive, but its a PITA to change.

    Hope this helps
    Joe
     
    #6 Joe 26, Oct 29, 2010
  7. andyprius

    andyprius Senior Member

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    I went thru this same thing. After changing coolant and inverter pump. Bled everything extensively. Inverter bleed was no problem. Engine bleed was trickier until I found the 6mm bleed valve. End result: Around town short trips 68 F at radiator. Long trip temps are 106 F, that is with a partial grill block. I have come to the conclusion that all this is normal, that the car has varying temperatures in various areas as needed. One does not notice these things until they arise and one gets involved. My car is not overheating, heater and AC are working fine. You are correct in not noticing any turbulance at the radiator fill spout, as in a normal car. I think the three way valve and the various sensors and the ECU involved does a incredible job of maintaining highly efficient engine temps. Beyond our comprehension!
     
    #7 andyprius, Nov 24, 2010
  8. 2009Prius

    2009Prius A Wimpy DIYer

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    Indeed it is beyond me how the coolant temp could drop from ~ 180 F at the ICE down to 106 F at the radiator. :confused: Smells really fishy. :rolleyes:
     
    #8 2009Prius, Nov 24, 2010
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  9. andyprius

    andyprius Senior Member

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    There is no overheating, no red triangle ????:confused: I never measured 180F, and can only assume at this point that the thermostat is working, when I get a IR meter then I will only know the temp at the thermostat location but not if it is opening???
     
    #9 andyprius, Nov 24, 2010
  10. andyprius

    andyprius Senior Member

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    My own theory is that the thermostat is never fully open, tied in with the fact that the car is cool running anyway it is possible that when the temp reaches opening point, it does open, a small amount, engine cools a small amount and thermostat closes again. In six years now I have experienced only mildly warm temps and slight pressure at the radiator fill point.
     
    #10 andyprius, Nov 24, 2010
  11. Joe 26

    Joe 26 Member

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    I wonder what happened to the OP?
     
    #11 Joe 26, Nov 24, 2010
  12. andyprius

    andyprius Senior Member

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    That's always a puzzling phenomenon, they just drop dead like flies, I guess? :D
     
    #12 andyprius, Nov 26, 2010
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