Head Gasket Repair - Anything else?

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by VicVinegar, Jun 10, 2025 at 10:35 AM.

  1. VicVinegar

    VicVinegar Member

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    Wanted to check and see if there is something else I should be considering before diving in to fixing the head gasket.

    I found a well-rated shop that ball parked me what seems like a reasonable price for the work, including sending the head out to a machine shop to check for any issues. I figured that if I do it, I'll also ask them to replace the EGR cooler and the water pump. My car probably also needs plugs.

    I'd like to check the traction battery health before sinking thousands into the car, I guess the Dr. Prius app is still the best way?

    Car has been running well overall, still got 50+ mpg commuting last week. Just ran into a real rough start over the weekend + P0301 code and now see the coolant is low.

    Anything else to consider here? Car is a 2013 with 172k miles. I realize the suspension is probably wearing out at some point, and there is still the brake booster lurking as well, but I don't think I've seen any value in a pro-active brake booster replacement. Thanks.
     
    #1 VicVinegar, Jun 10, 2025 at 10:35 AM
  2. BiomedO1

    BiomedO1 Senior Member

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    You may want to think about proactively replacing the invert coolant pump to avoid further downtime. Hold onto the old one as a backup spare.
     
    #2 BiomedO1, Jun 10, 2025 at 11:22 AM
  3. themzlab

    themzlab Junior Member

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    replace the thermostat and thermostat housing. I'm not sure you should bother with the water pump. They are very easy to replace and they don't have seals or bearings to fail like the old days. That said, I did this same job myself 3 years ago and I replace mine with a part straight from Toyota. I had a problem this year and I put the old pump back in. So, I guess what I am saying is if you do replace the pump, keep the old one around.

    I didn't do any machining on my cyl. head. The car hadn't done anything bad so I took a chance there wouldn't be a need for machining.

    replace the brake fluid although that is not directly related to any head gasket work.

    I cannot think of anything else that is warranted beyond what you have mentioned.
     
    #3 themzlab, Jun 10, 2025 at 4:28 PM
  4. Mendel Leisk

    Mendel Leisk Senior Member

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    I'd replace the water pump (aka pump for the engine coolant), and the thermostat. They are failure prone, due to plastic impellor swelling/cracking. And the inverter water pump. With the latter apparently the only way to get it out is to first pull out the inverter. Yup... Doubly frustrating: you can see it clear as day from below, but apparently the fasteners are only removable from above. At least according to @NutzAboutBolts .

    The EGR system entails EGR cooler, EGR valve, EGR pipe (between valve and intake manifold) and the intake manifold, which has EGR passages. All of it will be quite carbon-clogged, and I have this unproven theory that's what blew your head gasket. All of it likely will operate like new, with thorough cleaning, for around $35 (USD) to replace the pliable gaskets on the intake manifold. Or you can spend about a grand for replacement parts. More info in my signature (on a phone turn it landscape to see signatures).
     
    #4 Mendel Leisk, Jun 10, 2025 at 5:34 PM
  5. VicVinegar

    VicVinegar Member

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    Thanks for the responses. Now I see why replacing the whole motor becomes attractive.

    I'll talk to the shop owner I guess and see. Even if they weren't making money off parts, I could see a pro not wanting to mess around with cleaning out the EGR stuff.
     
    #5 VicVinegar, Jun 11, 2025 at 5:08 AM
    Last edited: Jun 11, 2025 at 5:21 AM
  6. Mendel Leisk

    Mendel Leisk Senior Member

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    Perhaps they could hand over the parts to you for cleaning?

    there is one component, the EGR valve, that is vulnerable to internal damage, a loose, internal component can develop a wear groove. Unfortunately you can only buy the complete valve, for over $200 USD.
     
    #6 Mendel Leisk, Jun 11, 2025 at 9:10 AM
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