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Compression leak down test advise

Discussion in 'Gen 3 Prius Technical Discussion' started by bobby515, Apr 20, 2024.

  1. bobby515

    bobby515 Junior Member

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    Question, 2011 gen 3.
    thinking guy's could be correct. have a defective egr, valve..broke. inside. have an oem comming.
    driven the car 10k since last june. no code's no oil or coolant loss.
    thinking the rumble on take off could be the head gasket.
    test equiment i have .
    cam scope coming today.
    head leakdown tester coming today...
    had regular compression tester.
    i still think it's the EGR..car has alot of power 202k on it.
    poor mileage..was getting 50 now for awhile 37..off and on it's good than not.
    i know my battery is weak.. repairing this today..got all the stuff tester's cell's etc.
    my question is. simple if its a compression loss from the head gasket could it last 10k mile's and while teating,
    beside's leakdown and visual inspection of the piston's and cly walls. where do i look for loss from...coolant reserve??
    oil cap..
    any thought's.
    if it''s the head gasket planning it next weekend..
    thank's
    also when i serviced the egr and cooler and intake month's ago car ran alot better than rumble or virbration during take off.
    does not happen always but alot..sometime's when gas engine kick's in..small rumble..sometime's not.
    want to rule out head gasket leaking..
    going to keep the car for 1 year or so..thks.
     
    #1 bobby515, Apr 20, 2024
  2. rjparker

    rjparker Tu Humilde Sirviente

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    Block the egr flow as described before to eliminate an open or sticking egr.

    Compression is not the problem

    There is not much else that can cause this once you rule out egr flow at low rpm’s. Coils, injectors and plugs don’t clear up.

    Head Gasket. The borescope can help if it is good enough to see steam cleaned cylinders where the coolant is leaking into the cylinder.

    The real issue is will a head gasket job result in a reliable engine? Usually not if you have run the car like this for weeks and months. A hg job does nothing for the rings. Timing chain alignment and cover replacement can be difficult with the engine in place.

    A rebuilt engine is a better bet. A budget choice is a JDM engine from a major city supplier.
     
    #2 rjparker, Apr 20, 2024
    Last edited: Apr 20, 2024
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  3. bobby515

    bobby515 Junior Member

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    Could I have been leaking headgasket air for 10k miles. And if yes. I use 1 qt oil in 5k miles. No coolant. Could it be possible that the head is leaking air. And if so. Waiting 10 k cause damage to the cly. Walls or valves not to do the head. I will know more tommorow. But soon I will block the air off at egr. Like shown.
     
    #3 bobby515, Apr 20, 2024
  4. rjparker

    rjparker Tu Humilde Sirviente

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    One qt in 5k is not too bad but is worse than not burning oil as reported earlier.

    From the sounds of it, your egr is/was sticking or stuck open which could have been the first or one of the problems. At low rpm’s the egr valve should be closed. Otherwise the engine will run rough or stall. At cruising speeds it should be open. A sticking egr at idle or low speeds will throw a code, typically a P0401. However you did not report that if I recall correctly.

    The thing is there have been thousands of these engines with leaky head gaskets and they all present symptoms just like yours. Typically without any “reported” cooling loss because the loss is small, at first symptoms are dependent on coolant pressure at shutoff and the small leaks are seemingly self sealing after startup. Until months later when the occasional rough start becomes every other time or, worse yet, everytime the engine cycles in operation.

    On top of those factors, car sellers will sometimes use head gasket sealers which can hold for five, eight or ten thousand miles.
     
    #4 rjparker, Apr 20, 2024
  5. bobby515

    bobby515 Junior Member

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    so you would not try the putty knief over the egr port. oem part coming wed. test equip late tonight. what would the putty knief show me covering the egr port??
     
    #5 bobby515, Apr 20, 2024
  6. bobby515

    bobby515 Junior Member

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    also i am preparing myself for a headgasket nest week if poor test result's
     
    #6 bobby515, Apr 20, 2024
  7. rjparker

    rjparker Tu Humilde Sirviente

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    Blocking the egr port will make the engine run smooth if the egr is causing the problem.
     
    #7 rjparker, Apr 20, 2024
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  8. bobby515

    bobby515 Junior Member

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    ok i am going to try this in a few minutes. thanks
     
    #8 bobby515, Apr 20, 2024
  9. Mendel Leisk

    Mendel Leisk Senior Member

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    5 threads now, on same topic. :confused:
     
    #9 Mendel Leisk, Apr 20, 2024
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  10. bobby515

    bobby515 Junior Member

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    Sorry .I am trying to do my best. I really appreciate all the manuals online you posted. It was a great help. I will continue and try to just read alot and not jump all over the place..
    The car still runs daily and is very dependable.
     
    #10 bobby515, Apr 20, 2024
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  11. bobby515

    bobby515 Junior Member

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    no go runs same rumble small when starting..goes away with normal idle. no coolant leak so far. no real oil loss in fresh change @ 1500 miles ago. oil cap clean inside. get tonight the test equip for compression and cly cam. for the cell phone..borascope?
    i was going to fix my low battery cells today. but thier still no codes. going to save my 61 y/o energy up for full test tommorow and if head gasket is bad, plan for next weekend...car still super reilable to drive daily.
     
    #11 bobby515, Apr 20, 2024
  12. Mendel Leisk

    Mendel Leisk Senior Member

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    #12 Mendel Leisk, Apr 20, 2024
  13. bobby515

    bobby515 Junior Member

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    Yes he was an older retired guy. In a wealthy area of .n.j , and I paid hi for the car @$5500. Because of car shortage.not a super clean car. But decent.
    Everything works. I have owned over 100 cars in 44 years driving. I agree with you 100% . Your help with everything was great. I downloaded the files you posted..
    Thanks
     
    #13 bobby515, Apr 20, 2024
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  14. Mendel Leisk

    Mendel Leisk Senior Member

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    That's a lot, must be an education. (y)

    Yeah the gen 3's reliably blow head gaskets, typically 150K~200K. For me neglect of the carbon-clogged EGR system is the very likely reason; other's are sceptical.

    You never want to put off cleaning the EGR, but start with the boroscope and/or leak-down testing. For leak-down test you want to have the cylinder at TCD of the compression stroke. Determining that can be tricky, I'm not clear how that's accomplished. This video shows a leak-down test. The guy is struggling with the valve set, ultimately figures things out by where the air is leaking out. But he does give tips on determining how to know if your TDC condition is compression or exhaust stroke.

     
    #14 Mendel Leisk, Apr 20, 2024
  15. bobby515

    bobby515 Junior Member

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    I needed a car as i sold my van in 1 say. wheelchair van. car's are so hard to get here. this is a $3000 car pre covid . running proper $6000 here all day long.
    worked for toyota 88-92 in SET southeast region . in florida. sold toyota's also. i am bodyman customizer by trade. worked on Cadillac when they were big in the early 80's..
    had an 08 308k pruis like new . all dealer serviced as seen on carfax. no one wanted to buy it..haha. today all will get in line for it.
    will post the #'s here tommorow, pkg deliver before 10pm .. amazon it says.
    just washed my wife's suv and it. this baby run's and run's . just think if the gasket is bad a head and valves are good . it will last me a long time. dont like having an 2011 ..but..thanks for you information. it's priceless. bob
     
    #15 bobby515, Apr 20, 2024
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