Suggested work during head gasket fix

Discussion in 'Gen 3 Prius Technical Discussion' started by Frontporch, Nov 11, 2025 at 8:19 AM.

  1. Frontporch

    Frontporch Active Member

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    I have a 2012 Prius with 200,000 miles on it. The head gasket currently does not leak and oil burning is probably about 1 quart every oil change. I recently cleaned the intake manifold in EGR cooler. PCV is new and a catch can was installed.

    I was considering replacing the head gasket as a preventative fix sometime this winter. I will be using a FelPro replacement gasket kit. I am looking for suggestions for other work that can be done while the head is off and the motor is partially disassembled

    With the pistons exposed is there any benefit to try and soak the rings for any length of time? Any products and procedures that have worked? I really don’t want to take the motor out to replace the rings.
     
  2. Mendel Leisk

    Mendel Leisk MMX GEN III

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    How come? People say the FelPro head gasket is better, but is it, or would a new Toyota gasket serve just as well? In other words, was the Toyota gasket “defective”, or is it’s failure (anticipated failure in your case), due to “extenuating circumstances” (EGR chock-a-block full of carbon). Too, with either the Toyota head-end or full-rebuild gasket kits, you’re getting a complete set of genuine Toyota gaskets/o-rings/seals, whereas (by reports here) the FelPro kit is less complete, and largely an assortment of “this’ll do”, generic.

    Also, FWIW, the Toyota head gasket has been revised

    How many miles between oil changes?
     
  3. Brian1954

    Brian1954 Senior Member

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    I would replace the engine water pump and thermostat if they have not been replaced previously.
     
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  4. JC91006

    JC91006 Senior Member

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    I feel it probably is not necessary to replace the head gasket prematurely. If you keep the car coolant relatively fresh (change every 50k) and replace the water pump every 150k miles, you should be good. I have a 2012 with 245k miles and a 2010 with 180k miles. Both all original engines but I've replaced the water pump and kept up the coolant changes. No symptoms of head gasket problems so far.

    It also doesn't hurt to keep the EGR circuit nice and clean, I feel this is usually a 1 time thing at 120k miles. I've checked mine at 200k miles and it didn't have much build up.