The invisible coolant leak.

Discussion in 'Heavy Duty Diesel Truck Mechanics Forum' started by Bugsy1108, Jan 19, 2022.

  1. Bugsy1108

    Bugsy1108 Light Load Member

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    This is a 2018 International LT.
    I've got a Cummins X15
    Just this week, and never before, I have a coolant leak that I cannot find.
    I smell coolant both under the hood on the passenger side and in the cab.
    There is no coolant smell to the exhaust or residue there.
    I've lost over over 2 gallons in about 10 days and can't find. It's not dripping that's why not dripping as far as I can tell.
    My food first fear when I noticed low coolant was an EGR cooler. But every time I've ever had that problem I didn't smell coolant and I found residue.
    The curious thing is that my most recent time checking the level it was below the minimum cold level and raised slightly above the minimum cold level when I took the cap off.
    The oil has been checked and there is no apparent Coolant or water in the oil. And the level of the oil has not risen.
    I'm sure heavyD will chime in with something brilliant.
     
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  3. Goodysnap

    Goodysnap Road Train Member

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    Pressure test and let set overnight in a dry spot. If it has an external leak it will show its face. The colder the better.

    I always do this before I look at internal leaks. The newer engines don’t have EGR cooler failure like the older ones did. Still can happen, but not that often.
     
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  4. jamespmack

    jamespmack Road Train Member

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    Psi test. Oil analysis

    Also check to see if transmission is over full on oil. If you have a water to oil trans cooler, or internally cooled trans.
     
    spsauerland, AModelCat and wonderdog24 Thank this.
  5. Bugsy1108

    Bugsy1108 Light Load Member

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    Is there a dipstick for the transmission on one of these? I've been told to check by the firewall, but there's nothing there.
     
    Last edited: Jan 23, 2022
  6. JonJon78

    JonJon78 Road Train Member

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    My X15 had a bad coolant leak that even with a pressure test, it couldn't be found...

    Mechanic let it sit outside ( temperature was around 0 )

    Turns out it was the coolant connection to the EGR cooler leading to the block...
     
  7. Bugsy1108

    Bugsy1108 Light Load Member

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    Found issue. Heater core.
    Thanks guys.
     
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  8. amtruck

    amtruck Bobtail Member

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    Feb 5, 2022
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    I have a coolant leak on N13 2015 i just had egr done. I can't find no systomps of it leaking on the groud i just had egr done last week. I'm adding about 2 gallons every 500 miles or so. But not all the time please help
     
  9. AModelCat

    AModelCat Road Train Member

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    Plug on the side of the transmission. Oil should be level with the bottom of the hole.
     
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