1. Thank you for visiting HeavyEquipmentForums.com! Our objective is to provide industry professionals a place to gather to exchange questions, answers and ideas. We welcome you to register using the "Register" icon at the top of the page. We'd appreciate any help you can offer in spreading the word of our new site. The more members that join, the bigger resource for all to enjoy. Thank you!
  2. ALL NEW MEMBERS READ THIS FIRST!! Thank you for joining Heavy Equipment Forums! If you are new to forums we communicate with "Threads", please search our threads to see if your topic may have already been answered and if not then click "Post New Thread" in the appropriate forum. This will allow all of our members to see your question and give you the best chance to be answered. After you've made a number of posts you will graduate to Full Member status where you'll see a few more privileges. Following these guidelines will help make this the best resource for heavy equipment on the net. Thanks for joining us and I hope you enjoy your stay!!

Oil in fuel 3126E

Discussion in 'Shop Talk' started by simonsrplant, Feb 9, 2020.

  1. simonsrplant

    simonsrplant Senior Member

    Joined:
    Feb 10, 2014
    Messages:
    484
    Occupation:
    Heavy Duty Off Road RSE
    Location:
    Alberta CANADA
    8YL67821
    Changed filters last set to note oil contamination in fuel. Had been using around a gallon or so in 200hours. Previously put it to wear.
    Seemingly apparent that it is actually going into the fuel.
    Changed all injectors for reman units from cat.
    No change.
    Have a fuel transfer pump to replace tomorrow.
    What else would cause this if it's not the transfer pump?
     
  2. funwithfuel

    funwithfuel Senior Member

    Joined:
    Mar 7, 2017
    Messages:
    2,687
    Occupation:
    Mechanic
    Location:
    Will county Illinois
    Aside from a cracked passageway in the head the only other thing I could suggest is the lift pump on the back of the HPOP. But I would think if that were a problem, you'd have a hard time maintaining ICP.
    Maybe Nige has come across this before.
     
  3. Nige

    Nige Senior Member

    Joined:
    Jun 22, 2011
    Messages:
    13,931
    Location:
    G..G..G..Granville...........!!
    I vaguely remember something about the pressed-in injector sleeves in the head. Can't for the life of me remember what it was though.
    Go with the obvious things as a starting point I'd say.
     
    DARO likes this.
  4. simonsrplant

    simonsrplant Senior Member

    Joined:
    Feb 10, 2014
    Messages:
    484
    Occupation:
    Heavy Duty Off Road RSE
    Location:
    Alberta CANADA
    Thanks Nige
    Question tho, injector sleeves have coolant the other side. I've seen them fail and put coolant in the fuel. Coolant in the water separator was the tell tale.
    That's the only reason I've not looked down that route
    Unless I'm mistaken... Happens!
     
  5. simonsrplant

    simonsrplant Senior Member

    Joined:
    Feb 10, 2014
    Messages:
    484
    Occupation:
    Heavy Duty Off Road RSE
    Location:
    Alberta CANADA
    If I'm right in my thinking, high pressure oil is at the top of the injectors, fuel rail beneath them and coolant at the base.
     
    DMiller likes this.
  6. Nige

    Nige Senior Member

    Joined:
    Jun 22, 2011
    Messages:
    13,931
    Location:
    G..G..G..Granville...........!!
    Yessir
     
    DMiller likes this.
  7. rmllarue91

    rmllarue91 Senior Member

    Joined:
    Apr 17, 2014
    Messages:
    506
    Occupation:
    field technician
    Location:
    northeast pa
    Seems the issues I've ran into with fuel oil mixing after cause was corrected it took longer than thought for oil or fuel to return to normal. I had 3306 with alot of fuel in oil dilution. ( Transfer pump was bad) it took 3 oil changes before oil looked normal. And black fuel can also take awhile to return to normal. I know your very experienced just a thought. In a hurry ended up new injectors and resealing unit pumps on that 3306 just because oil seemed diluted after issue was fixed.
     
    Truck Shop likes this.
  8. simonsrplant

    simonsrplant Senior Member

    Joined:
    Feb 10, 2014
    Messages:
    484
    Occupation:
    Heavy Duty Off Road RSE
    Location:
    Alberta CANADA
    Well, just changed the transfer pump.
    Guess we'll see...
    Not so much concerned with the oil in the fuel as much as oil usage

    Could suck the fuel out of my tanks but seems wasteful.
     
    rmllarue91 likes this.
  9. partsandservice

    partsandservice Senior Member

    Joined:
    Feb 14, 2011
    Messages:
    722
    Location:
    Georgia
    Typically oil in fuel is from a damaged injector oring.
     
    rmllarue91 likes this.
  10. Nige

    Nige Senior Member

    Joined:
    Jun 22, 2011
    Messages:
    13,931
    Location:
    G..G..G..Granville...........!!
    OP stated that injectors had been changed. I can't imagine that the o-rings weren't changed as well, actually Cat Reman injectors (If that's what was used) come with new o-rings already installed.
    Thinking out loud how long is it going to take for the oil contamination to go away from the fuel tank even after the source of the oil entry into the fuel system has been located and fixed..?
     
  11. funwithfuel

    funwithfuel Senior Member

    Joined:
    Mar 7, 2017
    Messages:
    2,687
    Occupation:
    Mechanic
    Location:
    Will county Illinois
    He's looking closely at oil loss over time. 1 gallon at 200 hours. Don't think that's a bad number if she's an old girl running at 50% or greater load. I'm curious what it's powering.
     
  12. Nige

    Nige Senior Member

    Joined:
    Jun 22, 2011
    Messages:
    13,931
    Location:
    G..G..G..Granville...........!!
  13. simonsrplant

    simonsrplant Senior Member

    Joined:
    Feb 10, 2014
    Messages:
    484
    Occupation:
    Heavy Duty Off Road RSE
    Location:
    Alberta CANADA
    Nige
    You are correct. That is the old girl.
    When I did the injectors, the tanks were close to empty. Filled both with clean fuel. Not sure how long it will take to work it's way out of the system.
    Deviating from the original question then regarding oil usage...
    33k lbs running weight
    Fairly severe environment (up and down mountains)
    Compression brake
    High hour motor good service history and runs well
    What would the expected oil usage be?
     
  14. partsandservice

    partsandservice Senior Member

    Joined:
    Feb 14, 2011
    Messages:
    722
    Location:
    Georgia
    Pits in the bore where the orings lie will allow leakage of HPO to fuel gally.
     
  15. simonsrplant

    simonsrplant Senior Member

    Joined:
    Feb 10, 2014
    Messages:
    484
    Occupation:
    Heavy Duty Off Road RSE
    Location:
    Alberta CANADA
    Done about 170 hours since changing out the injectors and transfer pump.
    Not used a drop of oil and fuel seems to be significantly cleaner.
    Not sure which part was failed but at least my problem is fixed.
     
    rmllarue91 likes this.
  16. Nige

    Nige Senior Member

    Joined:
    Jun 22, 2011
    Messages:
    13,931
    Location:
    G..G..G..Granville...........!!
    Well as you stated in your OP that you had changed the injectors with no visible difference in the colour of the fuel, my money's on the transfer pump.
     
  17. simonsrplant

    simonsrplant Senior Member

    Joined:
    Feb 10, 2014
    Messages:
    484
    Occupation:
    Heavy Duty Off Road RSE
    Location:
    Alberta CANADA
    On face value I'd agree.
    Only questionable point would be time period for fuel to clean through from the tank.
    Also, in my experience the transfer pump typically fails in the opposite direction, diluting the oil with fuel.
    Either way. I'm happy!
     
    rmllarue91 likes this.