Fan belt is off. How do I tell if head is warped or if there is a blown head gasket?

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by LCG, Oct 10, 2018 at 5:23 PM.

  1. LCG

    LCG New Member

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    25531022-A648-4D1A-8EBD-82A3A445D285.jpeg Daughter came back from college reporting a noisy engine. (When driving above 50 mph) Temperature gauge warning light came on. The fan belt was off. How do I tell if a head is warped or there is a blown head gasket? Is this a reasonable repair or doomed engine?
     
  2. exstudent

    exstudent Senior Member

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    Who replaced the engine water pump belt? That is not an OEM belt. Next vehicle/engine, stick w/ OEM parts. After market parts, the fitment, durability, and quality oftentimes pales in comparison to OEM.

    My $ is on the engine being toast. If you can't DIY, start calling around for pricing on a used engine install.

    An Internet Search can provide the answer you seek.
    upload_2018-10-11_0-32-27.png
     
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  3. Dxta

    Dxta Senior Member

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    Its quite easy.
    1. Has there being any previous work done on the belt area before now?

    2 . Open the oil cap, or engine oil dipstick.
    Do you see any milky colouration in their? If yea, gasket problems already. If no, head is OK.

    3. Is the coolant in the radiator short, as a result of leaks?

    4. As long as the belt is off right now, you could by hand, turn all the accessory pulleys(water, etc), and feel if the water pump impellers are broken.
    That may account for the noise too.
    *** I don't think headgasket is gone.
    I can't remember off my head right now, but I think that water pump is driven by the accessory belt that just slipped off.

    The reasons for the slipping off if the belt, might be that the belt as elongated beyond normal, from extensive use(too old), or if there has being any previous job done, maybe the tech forgot to properly tension the belt by tightening the stud to proper torque.

    Replace that belt with its right size, and start the engine after confirming all the tests above.


    Dxta


    PS: the engine would always overheat, or bring up the temperature warning on the dash/MFD, if the belt that drives it is off, as in your situation.
     
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  4. jerrymildred

    jerrymildred Senior Member

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    If the engine is damaged, as seems likely, you should go back to the person who put on the wrong belt.

    But if she shut it off before the head warped, I'd still go back and let that person know that the made what could have been a very expensive mistake.

    Yes, that belt drives the water pump.

    The belt came off because it was the wrong one and didn't have the grooves to match the groves in the pulleys. It just walked right off.
     
  5. Raytheeagle

    Raytheeagle Senior Member

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    My bet is the belt tensioner was not snug, allowing slack to develop and the belt then is no longer on the water pump pulley:(.

    Check the radiator coolant level and see where it is at. If it is low, that’s one sign;).

    Good luck and keep us posted (y).
     
  6. edthefox5

    edthefox5 Senior Member

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    Belt probably jumped off because it’s wrong belt.

    Noisey engine after severe overheat=blown motor.

    Needs a new motor used motor installed is about $1500-2000. But if the car has an original hybrid battery that’s next on the to do list. Your new here the most posted subject is bad hybrid battery on a g2.

    If high mileage car I would not throw that kind of money at it. Get her into a Corolla.
     
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  7. TMR-JWAP

    TMR-JWAP Senior Member

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    What a bunch of doom and gloom.

    First things first. Replace the belt. Check the fluids and top off if needed. Start the car and see what it does. Take it for a drive through the neighborhood. See what it does. Go from there.
     
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  8. Dxta

    Dxta Senior Member

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    That's definitely, the right approach.
     
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  9. ETC(SS)

    ETC(SS) The other One Percenter.....

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    +1

    Would I repair and drive a 12-year-old car that's suffered a thermal insult?

    Yup!

    However (comma!!!!!!)
    I'm a middle aged driver with a three mile commute to work in a very low crime area with excellent cellar signal.....and I have a CCP, two back-up vehicles, and I can stroke a check for a replacement car.

    In other words my break-down tolerance is a little bit different than some others might be.
    If I had a child in college whose car might be the difference between them coming home to do laundry and get food - OR - being stuck in BFE standing on the side of the road and hoping that they have a good enough cell signal to coordinate a rescue mission then I might not be so willing to roll the dice on a motor that might or might not have a marginal head gasket, head, bottom-end, hoses, etc that at the very least just got heat-stress tested.

    OPs call.

    Me?
    I'd put my KID in another vehicle, and maybe keep the G2 as a project car......but that's me being me again.
     
  10. exstudent

    exstudent Senior Member

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    Nah. My $ is on the wrong belt is the cause of all the problems.
    upload_2018-10-11_16-36-53.png
    Picture from Post#29; How to replace engine coolant pump and thermostat | Page 2 | PriusChat

    If you compare the pictures of the OEM belt (here) vs the not-made-for-Prius Gen2-belt (post #1), the wrong belt will not sit nicely INSIDE the pulley, between the tracks, with NO possibility of coming off; breaking off the is a different problem. The not-made-for-Prius Gen2-belt clearly sits ontop of the ridges and come off the pulley.

    Prepare for the worst, hope for the best.
    Worst= blown head gasket, wraped aluminum head; cheaper to replace with used engine $2k+; A possible reality OP needs to be prepared for.
    Best= just the proper belt
    If this belt was replaced by a shop, OP will have to try and get the shop to pay for the damages.
     
  11. Usle

    Usle Junior Member

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    Pull the spark plugs one by one and do a cylinder compression test.
     
    #11 Usle, Oct 11, 2018 at 8:05 PM
    Last edited: Oct 11, 2018 at 8:19 PM
  12. padroo

    padroo Senior Member

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    If the head was warped or the head gasket was blown the procedure is the same. The head has to be removed and checked for warpage at a machine shop and a new head gasket installed. Try the other advice first.
     
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