Advice needed: Want to buy a T6500. How good OR bad is the 7.8L I-6 Isuzu motor?

Discussion in 'Medium-duty Truck Forum' started by BennyD, Dec 17, 2016.

  1. BennyD

    BennyD New Member

    Hi guys, I'm new here and am looking for some T6500 or Duramax/Isuzu diesel engine advice. I only have experience with a few Powerstrokes, 3 DT466's, and a small CAT and small John Deere diesel.

    Advice needed: How good OR bad is the 7.8L I-6 Isuzu motor?
    I have the opportunity to get what is supposedly a good running 1998 0r 2000 GMC T6500 cabover with an Isuzu I-6 7.8L diesel engine in it. I am in the tree business and want to put a big 14' chip box heavy dump body on it and haul a big chipper with it! I can get the truck for a good price, but it does have 220k miles on it. How good or bad or reliable or unreliable is this motor? I have heard they also come with CAT motors, should I look for a CAT instead?
    I am ALL ABOUT preventative maintenance, so I change oil and fuel filters all the time, but I do not want to be replacing an engine in this thing!
    Anyone have much experience with these motors or know much about these motors? I believe it is a Duramax/Isuzu 6H I-6 7.8L that's in this particular truck, but thats all I know. Is it strong, reliable, and long lasting, will it go the long haul? And how does it compare to the CAT motors that they also put in these trucks?
    Thank you for ANY advice at all. I REALLY want one of these trucks.

    Ben, in Boston
  2. squatchy

    squatchy Rockstar 3 Years 1000 Posts

    There's a reason GM partnered with Isuzu to design and produce a diesel motor customers would actually want.
  3. BennyD

    BennyD New Member

    Can you elaborate? Would you prefer it over the Catepillar motor that also comes in these trucks? I wonder which is more reliable.
  4. squatchy

    squatchy Rockstar 3 Years 1000 Posts

    You need more elaboration than General Motors sought out Isuzu to build their diesel engines? Cats are a toss up if its a c7 youll have issues if its a 3126 itll be garbage at those miles. Isuzu motor is gonna pull better than a cat.

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