Source of blowby (link to vid)

Discussion in 'Heavy Duty Diesel Truck Mechanics Forum' started by C15Mike, Nov 26, 2018.

  1. Nov 26, 2018 #1
    C15Mike

    C15Mike Light Load Member

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    I've been having increased blowby out of my breather tube in the last 2 weeks. I decided to run the overhead just to make sure nothing was off. While I had the valve covers off I recorded a vid of the blowby coming up on the last valve cover which cover cylinders 5 and 6. Here is a link to the vid Can anyone tell me where this is coming from? Thanks for any help
     
    C15Mike, Nov 26, 2018
    C15Mike, Nov 26, 2018
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  3. Nov 26, 2018 #2
    spsauerland

    spsauerland Road Train Member

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    Probably coming up from crankcase thru oil drain casting on left rear of engine block or possibly valve stem seals. Looks like it is getting tired...
     
    spsauerland, Nov 26, 2018
    spsauerland, Nov 26, 2018
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  4. Nov 26, 2018 #3
    C15Mike

    C15Mike Light Load Member

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    Thanks for the fast reply! I also notice seeping between the spacer plate and the block on the right side of the motor. Could this be related? I did the bottle test and no bubbles were present. I was worried since I really don't want to tear into the motor over the winter but if I need to than so be it. I really don't know too much about this motor except it has 850k on it and the guy I bought from said it was inframed about 300k ago but had no paperwork proving it.
     
    C15Mike, Nov 26, 2018
    C15Mike, Nov 26, 2018
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  5. Nov 26, 2018 #4
    A5¢

    A5¢ Medium Load Member

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    What is the oil consumption? It would be good to know what was, or wasn't done to the engine during it's in-frame.
     
    A5¢, Nov 26, 2018
    A5¢, Nov 26, 2018
    #4
  7. Nov 26, 2018 #5
    C15Mike

    C15Mike Light Load Member

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    Consumption has gone up since I noticed the blowby to about 1 gallon every 1,500 miles. Not sure what was done or if it was even overhauled.
     
    C15Mike, Nov 26, 2018
    C15Mike, Nov 26, 2018
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  8. Nov 26, 2018 #6
    A5¢

    A5¢ Medium Load Member

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    Perhaps an oil diagnosis would be in order to see what's swimming around in the crankcase? It would be a good place to start and see what the sample says.
     
    A5¢, Nov 26, 2018
    A5¢, Nov 26, 2018
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  9. Nov 26, 2018 #7
    BoxCarKidd

    BoxCarKidd Road Train Member

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    Turn the engine so the exhaust valves are loose on the back two cylinders, one at a time. Push on the spring retainers side to side. I saw one with very bad stem to guide clearance.
     
    BoxCarKidd, Nov 26, 2018
    BoxCarKidd, Nov 26, 2018
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  10. Dec 7, 2018 #8
    DieselTech_Aus

    DieselTech_Aus Light Load Member

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    that has a broken ring or its grabbed a skirt and the liner and ally skirt are all scored up. its from either cylinder 5 or 6. best bet is run it like that and use ET to cut out cylinder 5 and 6 one at a time allowing at least 30 seconds for the haze to clear and see which one when cut out clears up the crankcase smoke.

    I wouldn't advise driving it like that. if the skirt fractures it will allow the piston crown to turn 90 degrees in the bore generally resulting in a vented block.
     
    DieselTech_Aus, Dec 7, 2018
    DieselTech_Aus, Dec 7, 2018
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