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Liquid Sloshing when turning on/off

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by jk823, Jun 2, 2018.

  1. jk823

    jk823 Junior Member

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    hi!

    I have a 2009 Prius with about 95k miles on it. A few months ago the Check
    Engine light came on and I brought it by my mechanic who read the code (I can’t remember which it was — but it was a common one) and said the Auxiliary Water Pump needed to be replaced. He did that and since then almost every time I turn the car on/off I hear a sloshing liquid sound.

    I brought it by today and he said “there may be air in the system” so he bled it but when I got home (of course) and turned the car off the sloshing noise returned!

    Any ideas?

    Thanks!
    John
     
  2. bisco

    bisco cookie crumbler

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    does he have tech stream?
     
  3. jk823

    jk823 Junior Member

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    I’m not sure what that is. I can ask?

    I saw Patrick Wong suggested elsewhere that it could be air in the heater core? Should I try these steps? (although I worry about introducing air into the system if I open the radiator cap...)

    1. Make the Prius READY
    2. Turn the heater temp control to MAX HEAT and turn the vent fan to maximum speed.
    3. While the car is in P and stationary, rev up the engine as fast as it will go, which is only ~3K RPM or so. Keep revving the engine for 10 minutes - or until you no longer hear air bubbling in the heater core.
    4. Make the Prius IG-OFF and let the engine cool down.
    5. Check the radiator fluid level in the radiator itself as well as the overflow tank after the engine is cold; replenish as necessary with the correct Toyota Super Long Life Coolant.
    6. Drive the car and make sure you no longer hear air in the heater core - if you do then repeat 1-5 above.
     
  4. bisco

    bisco cookie crumbler

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    if patrick recommends, you can take it to the bank. toyota tech stream diagnostic software is the official way to bleed the air out, but patricks and other workaround are fine if done properly.

    a mechanic inexperienced with prius might not know this.
     
  5. jk823

    jk823 Junior Member

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    Cool.

    Forgive the stupid question but when it says “Check the radiator fluid level in the radiator itself as well as the overflow tank after the engine is cold” would you take it to mean opening the radiator cap in addition to checking the standard reservoir?
     
  6. LEVE

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  7. bisco

    bisco cookie crumbler

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    yes, the reservoir doesn't tell the whole story. it could have coolant in it, but the radiator can be low.
    you have to remove the plastic cowling to get at the radiator cap, so most people don't bother.
     
    Raytheeagle likes this.
  8. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Is the check engine light (CEL) still on now?

    The engine coolant heat recovery system pump is supposed to run for a few seconds upon startup and shutdown. Perhaps that is the sound that you are referring to, and if so then this is normal. The purpose of that pump is to move hot coolant upon shutdown into the coolant heat recovery system canister located in the front left wheel well. Upon startup, coolant is moved from the canister into the engine, to speed engine warmup, thus reducing engine startup exhaust emissions.

    Turn on the cabin heater by setting the temp control to MAX HEAT and turn the fan switch to the fastest position. 1) Does the heater produce lots of heat, and 2) do you hear any air bubbles in the heater core? If your answer is yes to 1) and no to 2); and the CEL is not on, then you don't have air in the engine coolant system.
     
  9. jk823

    jk823 Junior Member

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    Thanks for the replies.

    CEL is not currently on and hasn’t been since they replaced the auxiliary water pump.

    Not sure I hear any bubbles in the heater core — does that mean just the heater itself? Would I hear them from the drivers seat? I will test this and report back.

    I did check the coolant levels and it was really low in the reservoir so I filled that. (I checked under the radiator cap and saw a liquid so I assume that’s fine.)

    Maybe adding cooland solved the issue?
     
  10. Patrick Wong

    Patrick Wong DIY Enthusiast

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    You would hear the air bubbles from the driver’s seat.

    The radiator fluid should be full, at the top of the opening.