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Can head gasket replacement cause water pump to fail?

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by Matt M., Apr 26, 2023.

  1. Matt M.

    Matt M. Member

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    I have a 2012 Prius Four with 170k miles. It's been great, no major repairs until now.

    A few months ago my coolant level started slowly draining, so I would add some coolant every couple of weeks to keep it full. Eventually my high coolant temp light came on briefly a couple of times, so I took it to an independent shop, they did a test and said the head gasket is leaking. Then I took it to our local dealership without telling them I had already gone to another shop - they also did a test and said the head gasket was leaking.

    Since the cost estimates were about the same, I decided to spend $5k and have the dealership replace the head gasket, which took 2 weeks. Then I was really hoping I wouldn't have to do any unscheduled maintenance for a while and could just drive the car for a few more years.

    After getting the car back, I made a couple of very short trips and everything was fine. Then I drove about 40 miles. Driving there I had no problems. On the way back, the high coolant temp light came on a couple of times for 10-20 seconds each time.

    When I got home I looked under the hood and the engine coolant level in the reservoir was near the bottom of the tank, which is far below the "low" line. So either the dealership didn't top off the coolant when they did the repair, or I had a serious leak.

    I took it back to the dealership and they said there's a code indicating that the coolant pump isn't working, so it needs to be replaced. He said when I brought the car in originally they checked everything and there was no code for a water pump problem. Their normal price for a coolant pump replacement is $1200, but they'll do it for me for $900.

    To me, it seems like a very hard-to-believe coincidence that the water pump failed immediately after the head gasket was replaced - just based on timing, it seems very unlikely that this was a random failure. Is it possible that the dealer did something during the head gasket replacement that damaged the water pump? I know there's no way to prove that, but I really don't like the timing of it. If I only had the dealer's diagnosis of the original problem I would even suspect that the original problem was a failed water pump and not the head gasket, but since another shop also independently diagnosed the problem as a head gasket leak, I have to think that there really was a leak. But this water pump failure on my very first long drive after the head gasket replacement seems like such a crazy coincidence. Also, would a water pump failure cause a lot of coolant to leak out? Because I still don't know if the dealer didn't top off the coolant when they did the repair, or if it leaked out very rapidly somehow.

    Any opinions or relevant experience would be greatly appreciated!
     
  2. ChapmanF

    ChapmanF Senior Member

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    The coolant leak sounds like somebody goofed. Otherwise, I wouldn't have expected a head job to hurt the water pump. The mileage is around where the water pumps sometimes conk out anyway; I think if I had been doing the head job, I might have changed the pump just because ... to avoid possible overheating after an expensive head job.
     
  3. CR94

    CR94 Senior Member

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    No, but pump problems can cause head gasket failure.
    and
    Failure to get all the air bubbles out when refilling after a head gasket replacement might cause overheating.
     
  4. rjparker

    rjparker Tu Humilde Sirviente

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    Odds are good the water pump was going bad to begin with, prior to the hg repair. It is not always an all or nothing failure.

    If coolant is not scattered all around the reservoir, I would suspect another head gasket failure. A hg leak typically allows coolant to be consumed in the combustion chamber.

    You might want to take it to Gasketmasters for a second opinion.
     
  5. Mendel Leisk

    Mendel Leisk Senior Member

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    Has the EGR system been cleaned?
     
  6. MikeDee

    MikeDee Senior Member

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    What, now EGR causes water pump failure!


    iPhone ? Pro
     
  7. Mendel Leisk

    Mendel Leisk Senior Member

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    I think I just asked a straightforward question. It's at 170K, and has blown a head gasket.

    Another question for OP (if I may): how long have you had it, since what miles? Any chance it had gasket sealer added to the coolant?
     
    #7 Mendel Leisk, Apr 27, 2023
    Last edited: Apr 27, 2023
  8. MikeDee

    MikeDee Senior Member

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    What about the 12v? Everyone seems to blame that for all manner of ills.


    iPhone ? Pro
     
    Mendel Leisk likes this.