3406e Oil Pressure Dropping

Discussion in 'Heavy Duty Diesel Truck Mechanics Forum' started by Jordonh, Dec 9, 2023.

  1. Jordonh

    Jordonh Bobtail Member

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    Hello Ya’ll?

    Currently have a FLD120 with a 1LW 3406e with 260,012 miles on it and recently been losing oil pressure dropped from 70 in the summer to 40-ish when winter started rollin in idles at 41 and cruises at 43-44. I know the issue I’m having but it may be something else as well. So recently been small oil leaking near air compressor hose and oil purging out of air cartridge none are coming out of my tanks which is good and after it started been noticing oil dropped from 70 to 65 to 55 to now in the 40 psi. It only stays in the 40 psi range now when it idles up and pulling a load

    Me and my pop’s are not sure if it can be either that or a bad oil pump/regulator or bearings need changing. We haven’t pulled the bottom off or did an oil sample to find the issue when we did its first oil change. Just want clarification on this.

    fyi changing compressor when I rack up a little more money!
     

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    Last edited: Dec 9, 2023
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  3. Smellfunny

    Smellfunny Road Train Member

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    I would hook a manual gauge into the engine some where to verify readings first (your gauge on an older truck might be a hard line to the engine not sensor read but I am not sure). I would still try a gauge on it. When was the last service? Are you using CAT filters?
     
  4. Jordonh

    Jordonh Bobtail Member

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    People I also asked are saying the same thing could be my gauge as-well will have to order an adapter first to hook to my tablet/laptop. It was last serviced at 242,819 and using Baldwin Oil Filters. Is it recommended to use CAT brand filters any difference?
     
    Oxbow Thanks this.
  5. Oxbow

    Oxbow Road Train Member

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    I shouldn't think it would be an oil pump problem if it still idles at 40 psi. As mentioned it could be a bad sendor or gauge. Plumbing in a manual gauge would answer that question.

    I believe the construction and filtration of Cat filters are better than aftermarket, and they really aren't that expensive (especially compared to the fuel filters on my new pickup...sheesh).
     
  6. Jordonh

    Jordonh Bobtail Member

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    Thank the lord :biggrin_2559: cause I’m fixing other things on the ole girl. I do plan on changing things on the bottom side or at least checking things out when the time comes though. Gonna change all my sensors on the motor cause they’re all old and haven’t been changed ever since. (When the original owner through in this 3406e in the truck)

    When I do my next oil change, I’ll be sure to install cat filters on my rig Thank u both!!
     
    Last edited: Dec 9, 2023
    Smellfunny Thanks this.
  7. Smellfunny

    Smellfunny Road Train Member

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    Yes I only use Cat filters on Cat engines. 1r-1808 for oil 1r-0749 for fuel and most of the time if it is a spin on 256-8753. The cat filters (especially fuel) are better. I would change oil every 12k-15k. Others have different opinions.
     
    InTooDeep, Jordonh and Oxbow Thank this.
  8. Oxbow

    Oxbow Road Train Member

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    ^^^^^^^^ Same here.
     
    Jordonh, cke and Smellfunny Thank this.
  9. BigCam9670

    BigCam9670 Medium Load Member

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    Any sign of fuel in the oil?
     
    Stay Puft, Jordonh and BoxCarKidd Thank this.
  10. Jordonh

    Jordonh Bobtail Member

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    No sir, always check my oil whenever I take off or when at my delivery’s or just in general. No signs of any type of fluid in the oil.
     
  11. BoxCarKidd

    BoxCarKidd Road Train Member

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    This was one a B not an E but an O/O where I worked had low oil pressure and was out of state under load. Do not remember all the details but I thank he was in Chattanooga at a dealer. They replaced the oil filter and the pressure came right back up. Told him he was getting coolant in oil and causing the restriction in the filter. Do not remember the brand filters but oil pressure dropped a few weeks later. Bad liner O - rings.
    Oil sampling was not as good and used as often 30 years ago I suggest you do that.
     
    Oxbow and Jordonh Thank this.
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