Water pump replacement need advice on mechanic estimate

Discussion in 'Gen 3 Prius Technical Discussion' started by irfanlai, Aug 21, 2025 at 11:19 PM.

  1. irfanlai

    irfanlai Junior Member

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    I have 2012 Toyota Prius 4 with 150k miles. I am getting following check engine light P261B

    This is my old post for the same issue Radiator dashboard lights ON...what does it mean | PriusChat

    Radiator light is getting On, Coolant was getting empty after driving at a speed of 70 mph. Once car went into limp mode.

    Mechanic diagnostic findings:
    Under Vehicle:

    Oil leak on rear of motor possible head gasket leak or timing chain tensioner leak start at top of engine and work down valve cover gasket starting to seep oil on rear of motor. recommend replacing valve cover gasket pressure washing engine and readvising.

    Tested for power and ground at water pump connector found good voltage and properly grounded. Tested signal wires for pulses going in and out of the water pump found that the return had more pulses than needed causing codes in ECM. Watching live data when pump was commanded to 3,000 rpm actual calculated rpm was 6,000+. recommend replacing water pump and retesting. low coolant level most likely do to vehicle over heating and spraying out of coolant reservoir pressure tested system and found no obvious leaks. faulty water pump can lead to over heating. Recommend replacing thermostat housing due to overheating issues.

    Attached is the estimated cost report. I am confused with the repair cost. Do you guys think this is acceptable?
    Do you think its worth replacing it?
     

    Attached Files:

  2. Grit

    Grit Senior Member

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    Damn 2 posts for 1 issue?! Our society is craving for attention!
     
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  3. irfanlai

    irfanlai Junior Member

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    I wanted to make sure mechanic diagnostic can be focused on this post hence created a new one.
     
  4. Tombukt2

    Tombukt2 Senior Member

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    The monkeys from the Amoco commercial can do this job without consequence oh y'all May remember AAmco
     
  5. Mendel Leisk

    Mendel Leisk MMX GEN III

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    With 150k miles, I’d replace water pump, and thermostat, regardless.

    Regarding your mechanic’s attributing coolant loss to “spraying out of coolant reservoir”: is there any evidence of this? There’d be a mess I think. Citing the 150k miles again, it’s more likely to be head gasket failure, leaking coolant into combustion chamber(s).

    EGR system ever been cleaned?

    I concur with @Grit btw: always frustrating to see double post, on what’s essentially the same saga.
     
  6. BiomedO1

    BiomedO1 Senior Member

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    $73.19 for that beautiful estimate...... IMHO; find a small mom & pop shop without all those fancy expensive toys & also start looking for another car. Over the past month or two; there's a high likelihood that you've done irreparable damage to that engine by constantly overheating it. Water pump and thermostat are going to be the least of your worries - a band-aid; IMHO

    Good Luck....
     
    #6 BiomedO1, Aug 22, 2025 at 12:18 PM
    Last edited: Aug 22, 2025 at 5:19 PM
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  7. PriusCamper

    PriusCamper Senior Member

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    This pump is electric and is as easy as an oil change to replace... There's plenty of videos on how to do it on Youtube and you only have to drain coolant down a small amount. If you or a friend or family member has basic car maintenance skill, there's no reason to spend alot of money on this job.
     
  8. irfanlai

    irfanlai Junior Member

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    What is Thermostat housing? Just thermostat or housing is different?
     
  9. BiomedO1

    BiomedO1 Senior Member

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    One piece unit - old American cars are two separate units.
     
  10. rjparker

    rjparker Tu Humilde Sirviente

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    This sounds like a dealer or high end independent shop who followed Toyota instructions for diagnosing a bad engine water pump.

    If you had listened to Brian four months ago it would have saved many many engine overheating events. Others suggested spending a little money to get it diagnosed properly back then.

    So do I think "it's with replacing it"? Yes unless you can afford to trade it in now and get a better car. If you do nothing the engine will have to be replaced without a doubt. At the dealer it's at least $8k to do an engine replacement.

    Is it as simple as replacing a water pump four months later? No. You may well have damaged the engine already. There are key questions for you and your shop that must be answered.

    1. Has it EVER started up with a severe rattle and shake. Normally this rattling goes away in 10-30 seconds and everything seems great for the rest of the day or even for weeks.

    2. Given the amount of overheating inflicted on this engine, you should ask the shop if they inspected for a leaking head gasket. Using a borescope, not a compression, leakdown or coolant combustion gas test.

    3. How much oil does it burn?

    If you have a head gasket problem now, you should consider replacing the car like your first mechanic advised.

    Finally is $1700 + a good price for a water pump, thermostat and shop supplies. It's good enough at a dealer who will put on $500-$600 worth of parts (retail prices) with the rest labor.

    ONLY use an oem water pump. There are cheap Amazon pumps but they usually fail in months or right out of the box.

    Could you get it done for less labor? Depends where you are but yes is the usual answer. But you need to be honest about any bad starts and you need a borescope test for a head gasket leak (which is very common on this generation of Prius). Plus your engine needs help now.

    I suspect you know very little about how this car works, common problems or diy repairs. It might be worth finding someone to help you sort this out.

    The screenshots below are discounted online parts. It may take a week to receive online parts and most good shops won't put them in for you. So you end up paying msrp (also shown) for the major parts plus new coolant, gasket sealer clips etc (shop supplies). Plus labor.
     

    Attached Files:

    #10 rjparker, Aug 22, 2025 at 4:38 PM
    Last edited: Aug 22, 2025 at 6:58 PM
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  11. Grit

    Grit Senior Member

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    For the ADHD,
    Make sense.