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Cleaning carbon deposits

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by JC91006, Apr 20, 2014.

  1. alekska

    alekska Active Member

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    Clip #3 sounds like a valve noise to me - too much clearance.

    - Alex
     
  2. JC91006

    JC91006 Senior Member

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    I'm suspecting the sound is a valve lifter noise but it would be very hard to tackle this problem. Looking at the repair manual, seems like you have to remove the timing chain to do it.

    The valve adjustment will take nearly the same amount of time as an engine swap, just you don't have to drop the engine. Galaxee has a write up about the adjustment, quoting him "it's a serious PITA" job. what to do...what to do.....
     
  3. Patrick Wong

    Patrick Wong DIY Enthusiast

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    I agree that #3 is valve noise, not a knock.

    BTW, Galaxee is a "she", not "he". Her husband had been a master Prius mechanic before he changed careers.
     
  4. JC91006

    JC91006 Senior Member

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    Is it normal for valves to get loud when the engine warms? I thought it was the other way around where valves are noisy when cold and quieter once warmed??
     
  5. Patrick Wong

    Patrick Wong DIY Enthusiast

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    The valves will get noisy when the clearance increases. Apparently as the engine warms up, the clearance is increasing. The Prius at best sounds like a noisy sewing machine anyway.

    What mpg are you logging on this car? If it is reasonable then I would say not to worry, just drive it.
     
  6. JC91006

    JC91006 Senior Member

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    I don't get as good mileage as I do with my others, I would say 40-45mpg on the average. It's much better on local driving vs. highway driving. Highway I would get close to 40mpg. (based on going from Los Angeles to Vegas)

    The MFD will show my average as 47mpg, but that's not an accurate number.
     
  7. Former Member 68813

    Former Member 68813 Senior Member

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    I can't hear any knocking.
     
  8. robert mencl

    robert mencl Member

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    to check for leaking valve guide seals, have a friend follow you in their car. decellerate at a preplanned place. If tailpipe smokes blue at that time, increased vacuum caused by decelleration is pulling oil by the valve guide seals, easy shadetree repair without pulling the head-use compressed air or clothesline rope to hold the valves up before you remove the keepers.
    You might check for a pcv issue.
    If you do scrap your motor, you might sell the head, sensors, etc. on Ebay.
    Carbon fouled plugs? Go hotter plugs one step at a time till they stay clean. Even if the pistons are carboned, you should be able to run the plugs clean.
    Have you looked in cylinders for carbon with a borescope?
    I used to use Marvel in my plane when burning no-lead auto gas, had no problems.
    If the only thing wrong with your car is burning oil, you've still got a good car. Run 'er till it gives you a better reason to turn wrenches. My 95 Saturn uses a quart every 600 miles, but gets 43 highway and is reliable as day 1.
     
    SFO likes this.