Peterbilt Cat C15 oil pressure problem

Discussion in 'Peterbilt Forum' started by trs100, Feb 14, 2012.

  1. trs100

    trs100 Bobtail Member

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    Hi,
    Does anybody know what is the normal oil pressure for C15 on idle when the engine is hot or cold?
    I`m getting around 20-30 psi on idle with hot engine since the manual says it needs to be between 40 and 80 psi.

    At 1200 rpm oil pressure is around 60 psi.

    Thanks!
     
    suuprmnn Thanks this.
  2. Mommas_money_maker

    Mommas_money_maker Road Train Member

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    How many miles since last oil change and are you full of oil on the dip and how many miles on the engine?
     
  3. trs100

    trs100 Bobtail Member

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    It has 1 007 000 miles and the oil is changed about 1000 miles ago and has lucas oil stabilizer.
     
  4. truckmechanic

    truckmechanic Medium Load Member

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    Sounds about what all our cats are running at
     
  5. trs100

    trs100 Bobtail Member

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    So is it a normal to be 20-30 psi on idle.

    The strange thing is that before it was around 60 when pulling and now goes no more than 45 psi with load.
     
  6. truckmechanic

    truckmechanic Medium Load Member

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    Have you ever rolled I'm main bearings the oil pressure relics valve might be getting week what oil filter are you running
     
  7. Mommas_money_maker

    Mommas_money_maker Road Train Member

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    I was thinking rods and mains bearings are due for change, they used to be changed around 725,000 and that would definitely cause a loss of pressure along with oil pump
     
  8. machesha1

    machesha1 Bobtail Member

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    Trs100.... I Have same problem on my cat c15 with 825000.
    Did you find out what was wrong with your engine?
    or give an idea what can be wrong.
     
  9. superhauler

    superhauler Super Crusty

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    before you start throwing parts at it. do an oil sample to see what metals are in it. it might be the oil filter collapsing or the brand of oil if you started using a different brand. it maybe fuel dilution ie bad injector or injector o-rings. oil sample will show that also.
     
  10. machesha1

    machesha1 Bobtail Member

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    Did the oil test....all good....Using same tipe of oil.
    On idle with 600 rpm i have 25psi with 180 F water temp.
    On 700 rpm 30psi
    On 750 rpm 38psi
    Full load 60psi and 50-55psi up hill with 210F water temp.
    Goind down hill 1500 rpm 60-63 psi.
    Conected to computer.... reading same like the gauge .
     
    Last edited: Feb 9, 2015