Head Gasket- what am I looking at?

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by C Clay, Mar 2, 2026 at 4:18 PM.

  1. C Clay

    C Clay Member

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    This is my first head gasket job. This looks horrible- not really like the pictures you see with a breach between cylinder 1 and 2. This has been on for 100k miles.
    Symptoms:
    Used about 10 oz of coolant a week for about the last 2-3 weeks.
    Just last week I started getting P300, 301, 302, and I think 304, but not until then. Of course I've had some hard starts- but minor. No over heating (I have a scanner app I use every time)
    What is this? Normally I thought you would see a "steam-cleaned" piston and cylinder- they all look like this. (The green in coolant was that dye I used hoping to find a leak and not have to to this)
     

    Attached Files:

    #1 C Clay, Mar 2, 2026 at 4:18 PM
  2. PriusCamper

    PriusCamper Senior Member

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    My guess is because you caught it early and are ahead of the game... As in the coolant will clean out some of the carbon if you wait long enough.
     
    #2 PriusCamper, Mar 2, 2026 at 4:29 PM
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  3. Mendel Leisk

    Mendel Leisk MMX GEN III

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    Who put the Fel-Pro in?

    upload_2026-3-3_8-7-51.png

    It's a common rationale here, that since the Toyota head gasket failed, that must be the problem, so replace with Fel-Pro. Maybe some conflation?
     
    #3 Mendel Leisk, Mar 3, 2026 at 11:06 AM
  4. C Clay

    C Clay Member

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    Shop. I asked about that- they stated that there were some supply chain issues and they used whichever they could obtain- Toyota or Felpro; and in some cases if they couldn't get that - something else, I think it was Ishino Stone.
     
    #4 C Clay, Mar 3, 2026 at 11:10 AM
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