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3306 fuel in oil problem PLEASE HELP

Discussion in 'Dozers' started by George Poland, May 21, 2022.

  1. Old Magnet

    Old Magnet Senior Member

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    Me and my 80 year old brain have been thinking about your fuel contamination dilemma. It just occurred to me that what would be an obvious leak with old school stand alone injectors would not be so obvious when connections are buried under the valve cover.
    What I am referring to is on a somewhat rare occasion an injection line ferrule may have split or otherwise not seal. To check it out:
    1. Loosen the line nuts at the injection pumps one at a time with engine running to kill the injection pressure and see if at least one cylinder is loafing and not carrying the load.
    2. Pull the valve cover and run engine while looking for a leaking line connection at the injector.
    3. If you want to get fancy try the dye and light check like shown in the attached video.

    Seems this would fill the criteria for the symptoms you've given. Please let us know if you've done this already or how it works out. Good luck.
     
  2. Mbar

    Mbar Well-Known Member

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    I was going to suggest exactly what cmark did. Other than that. Dye the fuel and get a black light
     
  3. George Poland

    George Poland Member

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    interesting video, I appear to have diesel in my oil, but the injectors are not under the rocker cover. So the injector I assume in this case can not be the diesel in oil problem.
     
    tctractors likes this.
  4. Old Magnet

    Old Magnet Senior Member

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    Well, there goes that theory.....
    I still see where the Cat SIS trouble shooting for fuel in oil states injectors as a source.
    If not injectors it's back to the injection pump. About the only way I can see fuel getting into the oil is past the pumps. Rare to happen but seats can go bad with loss of sealing, housings can crack or distort.
    Unfortunately governor oil drain back and pump drain flow is to inaccessible areas where leak check is not possible on the engine. Leakage check would have to be done on the test stand. Also doesn't explain why changing the complete pump and governor unit still had the same results.
    If it's of any use governor drain is down through the support bracket and pump drain is out through the engine timing gears.
    I'm out of ideas.
     
    Last edited: May 28, 2022
  5. George Poland

    George Poland Member

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    injectors ordered. will be on 6.06 for collection, we will assume and see if it is ok
     
  6. George Poland

    George Poland Member

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    number 1007559.
     
  7. Old Magnet

    Old Magnet Senior Member

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    Be a good idea to do do my recommendation #1 anyway to check if one or more cylinders are having a problem.
     
  8. George Poland

    George Poland Member

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    what do you mean that 1 of the cylinders you mean the injector or the pressure (rings, piston, sleeve?)
     
  9. Old Magnet

    Old Magnet Senior Member

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    I was thinking injector but the check could indicate a weak cylinder for other reasons.
    If the injector was over fueling I'd expect smoke....which you don't appear to have.
    The 3306B injector pumps have a residual check valve that normally maintains 1000 psi in the line. Plenty of time for leakage if the injectors are faulty but again where's the smoke!!!!
    New injectors may not be the answer but at least that will eliminate one possible cause.
    Are you getting any help/advise from the shop that rebuilt your injection pump?
    You mentioned having an identical pump. Would it be possible to get that pump on a test stand for a more thorough check?
     
  10. George Poland

    George Poland Member

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    it is now being checked, I have to pick it up in a week, but first I will replace the injectors and we'll let you know it will work
     
  11. Old Magnet

    Old Magnet Senior Member

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    Here's some info on governor and pump lube oil flow. Would have to be duplicated on the test stand. Have them dye and check output oil flow for fuel, especially the pump section.
    3306B Inj. pump & gov. #1.JPG 3306B Inj. pump & gov. #2.JPG
     
    D5Dan likes this.
  12. Old Magnet

    Old Magnet Senior Member

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    Any news of progress?
     
  13. George Poland

    George Poland Member

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    Buddy, the delayed delivery of the injectors will only be around 20.06 or a few days later, I will definitely write what happens after the replacement. I picked up the second injection pump today which was in check and it turns out to be good. So only the injectors or the engine pressure that I am going to measure when replacing the injectors remain.
     
  14. George Poland

    George Poland Member

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    Hello. I installed the correct injectors and the oil in the fuel stopped coming, but I also measured the engine pressure and on 5 cylinders it is 26 bar and on 1 only 15 (the first from the gearbox side) I also did an oil test (I poured the oil into the cylinder and we measured the cylinder pressure again. has not increased) so probably one of the valves will be damaged and I will have to take care of it in the near future.
     
  15. Old Magnet

    Old Magnet Senior Member

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    Well, that's mostly good news. Thanks for the follow up info.
    Could be a ring problem with that one cylinder. If the injector in that cylinder was over fueling it would wash away the lubrication of the rings resulting in excessive ring wear and glazing of the cylinder liner.
     
    D5Dan likes this.