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Loud clicking noise on cold start

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by jsikora, Nov 24, 2005.

  1. jsikora

    jsikora New Member

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    Hello all...
    I just found this forum, and it looks great. I have a 2005 Prius with about 8,500 on it. I've noticed for the past few months that on a cold start (not necessarily cold out.. it started in late summer) that there is a loud clicking noise from under the hood. Sounds like a solenoid or switch from the electric motor, the gas engine doesn't necessarily come on for the clicking to occur, which makes me think it is the electrical engine. The clicking ONLY occurs for about 10 seconds, roughly 20 or so clicks.

    I have taken it to my local Toyota dealership. Here's what they have said. They told me that its a Pre-heater for the cooling system, or something along those lines. They seem to be pretty vague about this, since they told me "Oh, that happens after 7,000 miles.". Honestly, I don't believe them. They don't really seem to have a good explanation why the car would automatically start making a clicking noise after 7,000 miles, and not 1,000 miles etc. Has anyone heard of a cooling system pre-heater, or, better, has anyone had any clicking noises occur immediately after hitting the START button for about 10 seconds? This is frustrating, I think the car needs to go back to Toyota, but, I'd like to be armed with some information before I go.

    Thanks, and Happy Thanksgiving!
     
    #1 jsikora, Nov 24, 2005
  2. Tempus

    Tempus Senior Member

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    The (US) prius has a "Thermos" where it stores hot coolant when you turn it off. The thermos is located inside the left front fender.

    It can keep the coolant hot for up to three days.

    When you start the car, the hot coolant is pumped over the top of the engine block to 'pre-heat' it, shorten warm-up time, and decrease the amount of time the system has to run with a rich air/fuel mix.

    This is part of the emissions system.

    That's the sound you're hearing. If you sit in the car after you turn it off, you can also hear the thermos being filled.

    There is also a little buzzing that sounds like it's coming from under the steering column that you can hear as you drive when it's quiet. That's the brake fluid pressure pump.

    Some people report that the coolant pump has failed on them. The symptoms are that it just gets louder and louder over time.

    It's covered under the emissions warrantee because it's an emissions related part, so you have at leasts 8Y/100K (or more depending on your location) before you'd have to worry about shelling out for it.

    There may be pictures of the thermos in the files section here, do not know.
     
    #2 Tempus, Nov 24, 2005
  3. Bill Merchant

    Bill Merchant absit invidia

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    Tempus is right about the US thermos and recirculating hot coolant, but I've never heard it "click". I hear sort of a buzz as the pump moves fluid from the thermos to the engine.

    If you're hearing a strong clicking, it may be something else, though I don't know what. This is the kind of thing where you'd need to leave your Prius overnight at the dealer's, and ask that their Prius tech start it in the morning when cold.

    Though I might not trust the dealer you've taken it to...
     
    #3 Bill Merchant, Nov 24, 2005
  4. tumbleweed

    tumbleweed Senior Member

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    Welcome to priuschat jsikora. I've been hearing the coolant pump and the brake fluid pump since I first brought the car home. Could it have been doing it all along and you just didn't notice? Anyway you might consider putting your location in your profile. That way if any one else lives in your area they might suggest a dealer with a good Prius tech, also some questions are weather or climate related.
     
    #4 tumbleweed, Nov 24, 2005
  5. jsikora

    jsikora New Member

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    Thanks for all the replies. I live in Westchester County, New York. I've taken the car to Westchester Toyota, and they have had it overnight once, and said it was meant to do that. The sound is definately not a buzzing / pump moving coolant sort of sound, it is a loud clicking, as if something were opening and closing, or switching on and off. It is noticeable in the car as well as outside. It could be the pump, but, it would be a bad pump ready to go if it was. Does anyone know a good dealership in the White Plains / Yonkers, NY area?

    Thanks!
     
    #5 jsikora, Nov 27, 2005
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