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How to change the coolant flow control valve?

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by mike choi, Apr 8, 2013.

  1. mike choi

    mike choi New Member

    Joined:
    Apr 8, 2013
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    Vehicle:
    2004 Prius
    Model:
    Two
    I'd like to try this myself. Any ideas how long this would take? Tips? Thanks!
     
  2. tommymommy

    tommymommy Member

    Joined:
    Sep 26, 2009
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    Location:
    Texas
    Vehicle:
    2007 Prius
    Model:
    N/A
    Just did my 2006 prius.

    You will need:

    Phillips screw drive
    cable hose clamp pliers (Sears, Autozone, etc.)
    10mm & 12mm sockets
    2 gallons of Toyota SLLC coolant (about $22.00/gallon)
    1/2" OD x 3/8" ID tubing
    paperclip
    funnel ( I used the Lisle 24610 spill free funnel) Lisle 24610 Spill-Free Funnel : Amazon.com : Automotive

    You will need to remove the top cover at the front of the engine. It has several fasteners that pull out. I found if I use the Phillips screw driver to rotate it while giving gentle, upward pressure, they come out fairly easily. image.jpg Pic shows part removed.

    Then, remove the plastic skid plate under the car. (4 machine screws toward back of engine & the front screws from the driver's side to the screw that frees the front of this plate). Pic #2 image.jpg
    Pic is after plate removed.

    On driver's side, remove fastener next to mud flap close on engine side. (I also removed the mud flap to allow more flexibility of this plastic fender cover). Pull cover out from front of car to expose coolant storage canister. Pic #3 image.jpg

    Attach tubing to port on bottom of canister. Place other end into collection container & open yellow valve to drain. (I did not open the overflow tank or radiator cap to allow the vacuum to pull coolant from those areas. I ended up with just under 1 gallon of coolant at this point. THEN I opened the radiator cap & got another 1/2 gallon of coolant out through the tubing.) image.jpg

    Once the coolant has drained, use the cable hose clamp pliers to remove hoses from coolant control valve. Be sure to mark the top hose so it doesn't get switched when you go to reattach pump. I just wrapped a colored rubber band loosely around that hose. When removing the bottom hose, we found it easier to remove the hose from the coolant storage tank with the opposite end still attached to the pump. See P1121 - Coolant Control Valve Replacement (with pics) | PriusChat for pic of valve in car with hoses.

    There are two places where the pump attaches to the car. The one under the inverter on the side, is a 10mm. It was difficult to get off because of the lack of working space. I used a long extension with a swivel attachment) The other one is a 12mm nut. You can see it from the top fairly easily. I just used a long extension to get to it. Once removed the pump can be pulled out from the bottom of the car.

    Reverse process to reinstall.

    To add coolant, place funnel onto radiator. (Funnel comes with a variety of attachments to fit any car) Fill with coolant (I didn't close the cap on the overflow tank & ended up over full. Next time I'll try it capped.) You will notice it bubbling. It ran 1/2 gallon in over about a half hour. I added the remainder of the gallon & it went in over the next 1/2 hour or so. Once it would not take any more coolant, I put the car into inspection mode to run the engine continuously with the heater set to high.

    How to get the car into inspection mode: (borrowed from Motor.com)

    Other aspects of normal Prius operation affect our work out in the bays. For example, there are times when we want an engine to idle uninterrupted (for lack of a better description) for emissions testing, engine or ignition analysis, warm-up and so forth. When the car is in Park, this engine may idle, but only as long as needed to recharge the HV battery, then it shuts off. Although the engine does idle in Neutral, the system doesn't recharge the HV battery in Neutral.

    The simple solution here is to activate Inspection Mode. This lets the engine idle normally and allows the system to recharge the HV battery as needed. To activate Inspection Mode on the Prius, the following steps must be completed within 60 seconds:

    1. Keep your foot off the brake pedal. Then "power up" the car by pressing the POWER button twice.

    2. Next, floor the gas pedal and fully release it twice.

    3. Depress the brake pedal and keep it depressed with your left foot for the rest of this procedure.

    4. Shift into Neutral, then floor the gas pedal and fully release it twice.

    5. Shift back into Park, then floor the gas pedal and fully release it twice.

    6. Now the HV warning light on the multi-information display (TV-like screen) should flash. This warning light has the silhouette of a car with an exclamation point (!) on it.

    7. Push the POWER button. The engine should start and continue idling at about 1000 rpm.

    8. Press the POWER button one more time to shut off the engine. This last step also deactivates Inspection Mode.

    The important thing to remember here: Never, ever road-test a Prius while it's still in Inspection Mode!

    Add additional coolant as needed. When it stopped bubbling, I ran the engine at idle for about 10 more minutes then shut it off, since no more air came out.

    Locate the relay box on the back wall of the engine bay, just under the windshield cowl. Open & find the CHRS relay. Remove the relay (It pulls right out). Use a paperclip to jump across the top horizontal terminals for a few seconds at a time to activate the coolant pump. Do not run longer than 30 seconds to avoid damaging the pump. You should see more bubbles coming out of the radiator. Once they stop, activate again until no more air comes out. Pic #4 & 5 (borrowed from another poster, jreed) image.jpg image.jpg

    Check coolant overflow reservoir to ensure adequate coolant remains. Add coolant, if necessary. Markings are on back of tank on passenger side. In my case, I had to remove the overflow tubing from the radiator neck to drain the reservoir to the full level.

    Check coolant levels over the next several days. total fluid back in ~ 6.5 quarts.

    All in all, I paid $72 for the pump, $44 for the coolant, $33 for the cable pliers and $37 for the funnel. Total cost $186 plus about 4 hours of my (and hubby's) time. The dealership wanted $550 for this work.
     
    koolingit and nh7o like this.
  3. Patrick Wong

    Patrick Wong DIY Enthusiast

    Joined:
    Mar 8, 2008
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    Location:
    Green Valley, AZ
    Vehicle:
    2015 Prius
    Model:
    Two
    The Toyota repair manual doesn't say much about how to find the coolant control valve, so a good reference is TSB EG001-08. Note the suggested labor time is 2.1 hours.
     

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