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What is the silver cylinder below the Aisin water pump?

Discussion in 'Prius c Main Forum' started by SilverWagon, May 11, 2024.

  1. SilverWagon

    SilverWagon New Member

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    I went to change the water pump on my 2012 prius C. When I was under the car loosening the 3 bolts for the water pump, I saw a silver, cylindrical, device the size of a small coffee can, below the pump. I'm curious what that device is.

    I hear clanking/knocking sometimes when the engine is running. The sound seems to be coming from the left side of the engine. I changed the pcv valve. I'm about to change the spark plugs. Below is a link to another thread with the same issue.

    2012 Prius C Engine noise | PriusChat

    Thanks
     
  2. SilverWagon

    SilverWagon New Member

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    I finished installing the engine coolant pump and noticed the cylinder below it is also made by Aisin. I couldn't get a good look to find more markings.

    I drove the vehicle around today and didn't hear the sound, I mentioned in the comment above, again. I'll report back if the sound comes back. Now I'm on to replacing the sparkplugs but I need a socket that fits into the engine better. The one I have now doesn't grasp onto the existing sparkplug. I think the sockets walls are too thick.

    If anyone can tell me what that silver Aisin cylinder is at the bottom of the engine, that would be great.
     
  3. Mendel Leisk

    Mendel Leisk EGR Fanatic

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    Any hoses leading to it? Post a pic?

    previous owner installed oil catch can?
     
  4. Leadfoot J. McCoalroller

    Leadfoot J. McCoalroller Senior Member

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    That's your air conditioner compressor. Typically makes a high whine in use.
     
  5. SilverWagon

    SilverWagon New Member

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    I thought it looked like one but I think it's weird to be that close to ground. I assume they get damaged a lot from road debris. My car doesn't have a shielding. I need to look into one. Thanks
     
  6. rjparker

    rjparker Tu Humilde Sirviente

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    The electric AC compressor is one of the most reliable things on a Prius. And is controlled by a Neural Net. True story.
     

    Attached Files:

    #6 rjparker, May 18, 2024
    Last edited: May 18, 2024
  7. Mendel Leisk

    Mendel Leisk EGR Fanatic

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    Achilles heel on 3rd Gen AC compressor (others may be sim) is the 12 volt connector on the top of the housing, aimed up, a veritable rain gauge. Owners pressure washing their engine bay have reported corroded out connectors, and so far replacement was only option.

    On Gen 3 at least, worth checking, the connector has a tricky release mechanism; you need to pry outward on front-of-car side, just above base of connector, with something very thin (tip of pen knife blade works) and then it comes off easy. Squeezing the lever arm never worked for me.
     
  8. rjparker

    rjparker Tu Humilde Sirviente

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    Best not to pressure clean the engine as there are lots of exposed connectors including the ecu and fuse box. Some get away pressure washing the back of the engine when they have a common timing chain cover oil leak.

    On the AC compressor don’t disconnect the orange high voltage connector.

    IMG_5105.jpeg
     
    Mendel Leisk likes this.
  9. Mendel Leisk

    Mendel Leisk EGR Fanatic

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    Yeah the black (12 volt) connector is the problem, and difficult (impossible?) to repair. Release point, for checking:

    IMG_4176.jpeg