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Cat 3126 Oil leak

Discussion in 'Truck Talk' started by Jimmy, May 15, 2003.

  1. Jimmy

    Jimmy New Recruit

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    Mornin' Ya'all,
    Thought while I was here I would post about this lil' leak. Had it for some time & itjust kept getting worse so I figured it's a good time to fix it. Oil seeping around HUEI pump flange.Runs down side of block to pan & runs out both sides of pan making it an awful mess.
    $4.75 "O" ring seal repairs it but it takes all day on one like mine because you have to pull power steering & air compressor off to get to it. While I'm in there replacing all the "O" ring seal just for good measure only abot $40.00 worth but better now than on the road.
    Do it myself save the $400.00 labor Cat wanted.
    Jimmy
     
  2. Weave

    Weave Veteran Expediter Charter Member

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    Good move, Jimmy. DOT inspectors are gettting a little more strict with oil leakage now.
    CAT's HEUI (High energy unit injection) system uses engine oil to power the fuel injectors, and a lot of times if there isn't an external oil leak with the system, the system will spray oil into the fuel, causing numerous other problems, as there are other O rings up at the injectors themselves. One case on EO we had a guy loosing a lot of oil in his engine, but couldn't figure out where it was going. No visible smoke or external leaks, but loosing quarts by the hour. It was spraying into the fuel injector returns, and ending up in the fuel tanks due to bad injector seals. (Mixing chocolate with peanut butter!) A new injector set and a flush of the tanks cured it, but to the tune of lots of bucks. This has me wondering again.. does the use of Lucas oil treatment or similar products help keep the 3126's fuel system seals from drying out too, as the injectors are oil powered? I'll bet it does!
    -Weave-
     
  3. Jimmy

    Jimmy New Recruit

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    Weave,
    Thanks for the reply. I've heard of the problems you mentioned from other sources. I think the Lucas will help a lot. But those seals are like the same ones used in the old cat heavy equipment transmissions.
    I don't think lube hurts them but heat does them in. All I replaced were very brittle.Also this engine isn't nothing but seals anyway,only head gasket & turbo oil return flange gasket rest "O" ring type seals. Thanks again.
    Jimmy
     
  4. RobZip

    RobZip New Recruit

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    >One case on EO we had a guy loosing a lot of oil in his engine,
    >but couldn't figure out where it was going. No visible
    >smoke or external leaks, but loosing quarts by the hour. It
    >was spraying into the fuel injector returns, and ending up
    >in the fuel tanks due to bad injector seals.

    Another way to avoid oil crossover into the injector system is to keep the engine speed up when idling for long periods, 850 - 900rpm should do. 3126's will let quite a bit leak over unless you keep extended idle rpm up.
     

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