N14 sudden oil consumption with a topend knock

Discussion in 'Heavy Duty Diesel Truck Mechanics Forum' started by masteron, Oct 2, 2022.

  1. masteron

    masteron Bobtail Member

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    Hi there, any ideas what might be causing sudden oil consumption on a n14 celect plus…

    Oil pressure at idle 12 psi - running 30-35 psi

    It had some bent rods, changed them, it seemed like the injector was bad , and that was making the tick/ knock on the top end

    now it is starting to consume around a gallon a day

    dont know if it might be the valves or the injector which is bad
     
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  3. 062

    062 Road Train Member

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    Bent connecting rods? Did you change the whole cylinder pack or just rod?
     
  4. masteron

    masteron Bobtail Member

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    Pushrods .. sorry, 3 bent rods on # 3..

    I am not with the truck right now, operator a few cities away ..

    one mechanic says valves, another injector
     
    OLDSKOOLERnWV Thanks this.
  5. 062

    062 Road Train Member

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    I could see a valve not sealing causing oil consumption, but I don’t think a injector would.
    Maybe @OLDSKOOLERnWV @Dino soar have some thoughts. They run older 855’s
     
    OLDSKOOLERnWV Thanks this.
  6. masteron

    masteron Bobtail Member

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  7. W923

    W923 Medium Load Member

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    Maybe the injector was/is bad and caused the piston top to crack. Been down this trail with two of them. Both were customers of mine so I don’t know a lot about the history but that it was almost 100 percent caused by injector problems.
    The blowby was excessive on both to the point it was actually blowing oil out the blowby tube under heavy load.
    Maybe a turbo problem to. I had a plastic sac get sucked into an air filter once and covered a large portion of it. The turbo was pulling oil past its seal because there was to much restriction. It’s easily seen by removing a boot from the turbo side of the intercooler. Turbo may be fine in this situation.
    I highly doubt it’s valves if it came on fast like you said
     
  8. Big Road Skateboard

    Big Road Skateboard Road Train Member

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    A bad injector washing down a cylinder wall is possible, but other signs should be visible now.
     
    W923 Thanks this.
  9. masteron

    masteron Bobtail Member

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    Like , what should he look for ..
     
  10. OLDSKOOLERnWV

    OLDSKOOLERnWV Captain Redbeard

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    That oil pressure sounds low…..


    Smoke on initial cold start up?

    noise?

    check the air intake to see if turbo is bypassing?

    any oil in the fuel tanks making the fuel look dark?

    excess oil in the air tanks?

    if the cylinder is scarred bad for any reason you will probably hear a tapping noise towards the top of the engine.

    Oil thinned out front fuel?

    Lot of little things to look at, we can’t see it, but if we could we could possibly give better answers….
     
    062, AModelCat, Dino soar and 2 others Thank this.
  11. W923

    W923 Medium Load Member

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    Most likely will see unburnt fuel running out of the exhaust manifold joints or gaskets at each port. It’s going to be really black and stains everything most people mistake it for oil.
    Might also be able to pick up diesel fuel in the oil on a test. Might have something to do with the lowish oil pressure
     
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