Duramax Coolant Change Questions

Discussion in 'GMC Truck Forum' started by GMCPapa, Feb 15, 2010.

  1. GMCPapa

    GMCPapa Member

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    I have a 2005 GMC 2500HD Sierra with the Duramax. The manual says the coolant is good for 150,000 miles or 5 years which ever comes first. I have several questions on how I should go about that. It's the first time changing the coolant in this truck so please bear with me. I've done this in cars before by installing a Prestone flushing tee kit in the heater inlet line, draining the coolant, connecting a water hose to the flushing tee and running the engine with the ratiator cap off and the drain valve on the bottom of the radiator open and the water on and flushing the engine. Now I have several questions:
    Can I do the truck like that?
    I see what I think are two black rubber hoses going to the heater. Which one should I put the flushing tee into?
    The manual says use only DEX-COOL (silicate-free) coolant. Is this just to sell me a GM product or Prestone good enough?
    If anyone has any photos of the procedure or have directions I would appreciate a copy.
    Thanks in advance for any help you can provide. I'm like many on a fixed income and have to do many of these things myself. This is an expensive engine and I don't want to mess up.
    Thanks again for any help.
    Papa
     
  2. davbell22602

    davbell22602 Senior Member

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    welcome to the forum
     
  3. Case 7230

    Case 7230 Senior Member

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  4. leolkfrm

    leolkfrm Full Member

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    dex-cool is made by texaco, not gm.
     
  5. BernieB

    BernieB Senior Member

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    It's also not rated for use in diesels.
     
  6. davbell22602

    davbell22602 Senior Member

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  7. BernieB

    BernieB Senior Member

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  8. leolkfrm

    leolkfrm Full Member

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  9. Crmzendrgone

    Crmzendrgone Senior Member

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    Welcome to the forum. The way I would flush the cummins was just to drain it and then run water through it disconnect the inlet hose to the water pump them disconnect the oulet from the radiator and then run the water through, them put it all back together and fill with whatever % needed where you are at.
     
  10. BernieB

    BernieB Senior Member

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    Yes it does, and it also says to mix it with plain water, which has been proven since then to cause significant damage to any engine using Dex-Cool, not just diesels.

    Read what Mrjohnwayne and I both posted in this thread http://www.truckforum.org/forums/ford-truck-forum/19798-changing-out-the-anti-freze.html and you'll see that Dex-Cool was never intended for use in diesels, doesn't meet ASTM standards for diesel coolants, and has been identified as the reason for many, many engine failures in the last decade.
     

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