Running without Catalytic converter heat insulator

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by san475, May 30, 2026 at 9:04 PM.

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  1. san475

    san475 New Member

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    2007 Base Gen2 Prius

    My prius' Catalytic converter was stolen.. again.
    Classic.

    I am attempting to install an aftermarket cat myself, but the heat shield/insulator was damaged in the theft.

    I would love to replace everything, but am trying to spend as little as possible on the repair and the OEM Heat insulator (Toyota 58151-12220) is pricey, costs about as much as the cat kit.

    I've looked around on the internet but haven't found much information on people's experience running the car without the insulator.

    I was hoping to get some insight from someone with a bit more mechanical experience on just how bad of an idea this would be.

    My other options would be to somehow hobble together the part, or use some other heat insulating material to bodge a solution.

    Appreciate any info or shared experiences.

    Thank you ahead of time.
     
    #1 san475, May 30, 2026 at 9:04 PM
  2. BiomedO1

    BiomedO1 Senior Member

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    IMHO; there's a purpose for the placement of that heat shield. Manufacturers don't just shove random excess parts into cars and argue over extra pennies they need to spend on manufacturing. Leaving it OFF will allow heat to penetrate the firewall and floor boards; potentially melting plastic inside the passenger compartment and making your AC work harder.

    Your car - do whatever your like; just don't be surprised if a fire erupts behind the dashboard or you suddenly get operations issues due to melting wires.
     
    #2 BiomedO1, May 31, 2026 at 9:38 AM
    Mendel Leisk likes this.
  3. Mendel Leisk

    Mendel Leisk MMX GEN III

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    #3 Mendel Leisk, May 31, 2026 at 10:25 AM
  4. rjparker

    rjparker Tu Humilde Sirviente

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    Go to a junkyard (which for Prii is often at an independent Prius shop).

    Sams hybrid specialist.jpeg
     
    #4 rjparker, May 31, 2026 at 10:38 AM
    Last edited: May 31, 2026 at 11:38 AM
  5. Mendel Leisk

    Mendel Leisk MMX GEN III

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    You could even cobble something outa (unpainted) aluminum flashing, gauge plate, at least for interim.
     
    #5 Mendel Leisk, May 31, 2026 at 11:38 AM
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