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How do my pistons look?

Discussion in 'Gen 3 Prius Technical Discussion' started by Mkgcb, Aug 11, 2024 at 5:18 PM.

  1. Mkgcb

    Mkgcb New Member

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    Recently did a bit of work on my new to me Prius. New plugs, coils ,EGR+cooler, intake manifold, and pcv.
    Used a borescope to peak at the pistons.
    I'm not a mechanic, so anyone have opinions on the condition of my engine?

    Sorry for the potato quality. Cylinder 2 and 3 were closest to TDC. Past that, no clue on which is which.
    :)
     

    Attached Files:

  2. V Sport Wagon

    V Sport Wagon Member

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    Looks like you're burning some oil on 2 of them while the top 2 seem almost too clean like they getting washed with coolant.
     
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  3. Mendel Leisk

    Mendel Leisk Senior Member

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    Really hard to judge. It would help if you could keep track of which cylinder is which. Maybe too, crank the engine (manually, using bolt on end of crankshaft, at right end) so that each pic is at bottom-dead-centre. And focussed.

    What’s the miles on it? How recently acquired? How’s it running?
     
  4. Tombukt2

    Tombukt2 Senior Member

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    I would not be happy with that going on inside of any internal combustion engines that I own at the moment I can say that I mean if it was running correctly and not making a racket and all of that I might run it until I could be through with it but if it's one of my keeper vehicles I'll move over to another one and put this one in the bay and have a look at it when I have time that's why I have several generation twos so we're never under the gun and out of transportation that's when you make foolish decisions quickly and waste piles of money.
     
  5. BiomedO1

    BiomedO1 Senior Member

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    From the pictures alone; I'd guess that this motor has high mileage and hardened valve guide seals. This allows oil to drop into the combustion chamber causing that black tar on the piston heads. Even on the clean piston heads, you can make out the trail between intake and exhaust valve. I believe 'v sport wagon' is correct; there's probably a head gasket issue or someone has temporary patched it with some chemical head-gasket sealant - so they could sell the car. If the car is running OK now, there's no telling how long that sealant is going to "hold-up", assuming you don't run into cooling system issues (sealant partially occluding your cooling system). Luckily were going into the winter months, so your probably good til next spring or summer.

    Sorry for the bad news. You asked for opinions and I wouldn't have touched this one, unless it was FREE. That's assuming that everything else is in pristine condition.
     
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