Possible rebuild?

Discussion in 'Heavy Duty Diesel Truck Mechanics Forum' started by FREDthaCEO, Dec 1, 2025 at 11:09 AM.

  1. FREDthaCEO

    FREDthaCEO Bobtail Member

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    Good morning I have a NXS C15 acert with over 1 million miles I have excessive blowby and when I'm climbing up the hills It struggles under a load.. It looks like it has some oil leaking from the blowby tube and when I start it I see white smoke coming out of the stack.. my mechanic told me its time for a overhaul I just came here for a second opinion but I'm leaning towards and overhaul as well but if that is the case what is the preferred overhaul kit to get
     
  2. Lazer

    Lazer Road Train Member

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    Need a few more specifics. You say it pulls down on hills under a load, how much of a load? How big of hills. What is your oil consumption? Coolant consumption? How does it start from cold? Warmed up? What is the mpg?
     
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  3. JB7

    JB7 Heavy Load Member

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    "I have excessive blowby" Based on what, observing the tube? Did your mechanic take a reading?
    "when I start it I see white smoke coming out of the stack" This is normal for a diesel in cool/cold weather.
     
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  4. FREDthaCEO

    FREDthaCEO Bobtail Member

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    Hey thanks for your reply coolant consumption is good but after an oil change I will run for about two months and the oil pressure drops again when pulling any kind of load my truck struggles going up hill. I don’t have any issues with the cold start
     
  5. FREDthaCEO

    FREDthaCEO Bobtail Member

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    It was doing this in the summer
     
  6. wore out

    wore out Numbered Classic

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    White smoke is fuel that isn’t burnt. It has 3 normal causes.
    1. A small amount of coolant on top a cylinder
    2. Low compression in a cylinder
    3. A bad injector that is pissing fuel instead of spraying.


    On a CAT 1 is most common doesn’t mean that’s your problem. But at a million I can assure you the liners are low and it needs uppers for sure most likely lowers.

    The smoke out the blow by tube as well as oil is a sure sign it’s wore ### out
     
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  7. Big Road Skateboard

    Big Road Skateboard Road Train Member

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    Also normal when you have low compression.

    I think maybe a byproduct of something that causes low compression could cause white smoke and excessive blowby.

    But, I'm just a driver. I'd run it till you're losing a gallon every 2k miles.
     
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  8. Lazer

    Lazer Road Train Member

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    ‘At about 2 months, oil psi drops when pulling up a hill’.
    Approximately how many miles are on the oil at that time?
    Do you use the same brand/weight of oil at every oil change? Have you tried a different brand/weight of engine oil?
    What does ‘pulling down’ on hills mean to you? Does the engine drop 100 rpm? 200? 1000?
    Do you drop a gear? 2? 4? Years ago downshifting on hills was considered ‘normal’, nowadays it’s looked upon as a ‘burden’, ‘horrible’ ‘my god I have to do that?’
     
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