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tinkerer's avatar
tinkerer
Explorer
Dec 18, 2013

Cat C7 secondary fuel filter

After 30,000 plus miles on my C7 Cat I decided the finally change to secondary or final fuel filter that is mounted on the engine. I did some research and there was a thread in this sight with all kinds of advice of buying a primer, filling the filter with diesel fuel, ATF fluid, and kerosene. One person said don't put anything in the filter and that sounded good to me. I put the new filter on with nothing in it and prepared for the worst. The engine started right up and never missed a beat and runs great. Just thought i would share this.:)
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  • Spizzer's avatar
    Spizzer
    Explorer
    Dec 18, 2013
    I'm looking at having to do the same thing. Cat says to not prefill, many say to do it. Is your c7 the 350 hp? Did you do it from below or above? What filter did you replace it with?

    Thanks,

    Jeff
  • wolfe10's avatar
    wolfe10
    Explorer
    Dec 18, 2013
    Many would say you were lucky.

    Yes, if you have a Caterpillar secondary fuel filter base, there is a block-off plate that you can replace with a manual primer pump.

    I have worked on many, many diesels, and would not take that chance.

    No primer pump, fill the filter PROPERLY: The small outer holes are the INLET, the center hole the OUTLET. Slowly fill the outer holes with clean diesel, being careful not to get any in the center hole. OR as recommended, fit the manual pump.

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