1998 Century Class Coolant loss

Discussion in 'Heavy Duty Diesel Truck Mechanics Forum' started by draya93, Sep 19, 2022.

  1. draya93

    draya93 Bobtail Member

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    Hey guys, have a 98 12.7l in a century class. I’m having a real hard time diagnosing a coolant leak. Checked all radiator hoses, tubes, heater core hoses and don’t find any leaks or puddles on ground. I’ll lose about 2 gallons in about 6-8 hours of driving and about a gallon over night when I’m parked with it off. Anyone that can give me any tips before having a mechanic checking it out? It has power, no smoke out exhaust, no coolant in oil. Truck runs great besides this issue. Has about 400k on in frame. Thanks I’m advance.
     
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  3. AModelCat

    AModelCat Road Train Member

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    What's your engine oil level like? How about the transmission level?
     
  4. shatteredsquare

    shatteredsquare Road Train Member

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    does it have EGR? i saw a video of the EGR cooler being the mystery coolant thief but it wasn't a '98. where can that much coolant go and not be filling up the oil pan or becoming smoke
     
  5. draya93

    draya93 Bobtail Member

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    Engine level is fine, will check transmission level here shortly
     
  6. draya93

    draya93 Bobtail Member

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    No egr on this one
     
  7. aussiejosh

    aussiejosh Road Train Member

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    Your losing 2 gallons in 6 - 8 hours and there's no puddles very interesting very interesting indeed. No water in oil which eliminates a cracked head, although it would not be going through 2 gallons. If it was losing 2 gallons your check engine warning light (orange) should come on, and then the stop engine warning light (red), and then if you ignored it the engine would shut down. My only guess would be that some how the water is evaporating if there are no visible signs of leaks.
     
  8. 062

    062 Road Train Member

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    Check the fuel tanks also.
     
  9. wichris

    wichris Road Train Member

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    Air operated valve for the bunk heater. If it leaks it will dribble out while going down the road.
     
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  10. BoxCarKidd

    BoxCarKidd Road Train Member

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    Bad air compressor blowing it out the dryer. Have seen it but cannot imagine that amount and not seeing it somewhere.
     
  11. blairandgretchen

    blairandgretchen Road Train Member

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    Injector cups you're thinking?

    How long would a truck continue to run with that much dilution of coolant in fuel?

    2nd question - how much would a transmission hold if it was going in there?
     
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