Loosing oil pressure

Discussion in 'Heavy Duty Diesel Truck Mechanics Forum' started by Briggs647, Sep 18, 2018.

  1. Sep 18, 2018 #1
    Briggs647

    Briggs647 Bobtail Member

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    Jul 4, 2017
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    I have a 81 Cummins ntc 475 and I’m loosing oil pressure... if I hold the rpms at 17 18 the oil pressure will go up around 45 50 then drop to 35 ish I have changed the oil and both filters I used a scope and and tried to look In oil pan and did not see anything ... I don’t know where or what else to look at ... some have told me that’s normal but I don’t know and have never been around the 475 any help is appreciated thank you
     
    Briggs647, Sep 18, 2018
    Briggs647, Sep 18, 2018
    #1
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  3. Sep 18, 2018 #2
    BoxCarKidd

    BoxCarKidd Road Train Member

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    Aug 26, 2014
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    81 is a big cam I? One spin on oil filter on the engine? With an aluminum oil pan. Has a by pass and or pressure relief valve in the oil cooler check that out. Then I would pull the pan. Check piston cooling nozzles and look for bearing problems.
     
    BoxCarKidd, Sep 18, 2018
    BoxCarKidd, Sep 18, 2018
    #2
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