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GM C8500 Must warm-up 30-45 minutes before use

Discussion in 'Trucks' started by jimdamachine, Jul 17, 2020.

  1. jimdamachine

    jimdamachine New Member

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    Occupation:
    Telecommunications
    Location:
    Lihue, Hawaii
    I work in the telcom industry and am not a mechanic. Our mechanic told us that there is nothing wrong with our derrick digger, a 2003 GM C8500 w/ caterpillar C7ACERT engine. The catch is that we were told to warm up the engine for 30 to 45 minutes before using the truck. It sounds like a joke, but they're dead serious. Has anyone heard of such a thing before, and what recommendations do you have for us users of the truck?
    Thanks
     
  2. heymccall

    heymccall Senior Member

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    I've got a fleet of C7s. Never heard of such a thing, regardless of whether it's 90°F or -10°F.

    Shirley, they gave a logical reason?
     
    Spud_Monkey likes this.
  3. 92U 3406

    92U 3406 Senior Member

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    Sounds like a complete line of crap IMO. Unless there's more to the story. You should be able to start putting an engine under light loads after a couple minutes of idling during summer months.

    What was the reason the mechanic was looking at it in the first place?
     
    Delmer likes this.
  4. Tags

    Tags Senior Member

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    To warm up the hydraulics maybe?? That does seem right though, you're in Hawaii, not like it's cold, check fluids, start equipment for 5 min, and get to work...any chance the mechanic is breaking your stones a bit??
     
    Truck Shop likes this.
  5. jimdamachine

    jimdamachine New Member

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    Occupation:
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    Location:
    Lihue, Hawaii
    We were told nothing is wrong, they're not going to work on it, warm it up for 30-45 minutes first. The problem is there is no power and it's like in limp mode. Used it just twice, don't want to use it again.
     
  6. Birken Vogt

    Birken Vogt Charter Member

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    Those engines can be complicated and troublesome. They probably don't want to open a can of worms. Something is wrong with it but it sounds like nobody wants to find out. If you get paid by the hour then collect your money for the 45 minutes as well as the rest of the day. You might want to think about what your long term prospects are at an outfit like that.
     
  7. Delmer

    Delmer Senior Member

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    Something is wrong, they don't want to work on it, maybe because they couldn't figure it out.

    Probably will get worse, might get sent to the auction first. It will be left idling at the sale.

    Is this a hydraulic weakness or an engine power problem?

    If it's an engine issue, most trucks get started and maybe 30 seconds of idle before they pull away at any temperature they'll start at, usually down to 0, and down way below 0 with block heaters. Same with hydraulics, they'll whine and complain below 0, but very few sit around for 30 minutes waiting for the hydraulics to warm up.
     
  8. petepilot

    petepilot Senior Member

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    change the oil. the hp pump does not like thick dirty oil
     
    WaterDoc likes this.
  9. WaterDoc

    WaterDoc Well-Known Member

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    Keep the oil changed regularly and the C7 will give you years of good service.
     
  10. Birken Vogt

    Birken Vogt Charter Member

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    Not around here they didn't.
     
  11. WaterDoc

    WaterDoc Well-Known Member

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    Occupation:
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    Toronto
    I worked for a GM dealer from '97-08 so I dealt with the 3116, 3126 and C7 in all the variants. They had a few small issues but nothing overly problematic. The customers who had repeated problems usually had a few things in common.
    1, Bad maintenance.
    2, Not enough truck for the intended purpose (210hp in a heavy dump that tows a tag trailer).
    3, A combination of the above 2 points.

    It was no powerhouse, but slow and steady it would get the job done. Our terrain in southern Ontario is pretty flat but I can definitely see where one may want more power, but again it comes down to the right truck/engine combo for the task at hand.

    Now the 7.8L Duramax that replaced the C7.. wouldn't touch that one with a 10' pole.
     
  12. heymccall

    heymccall Senior Member

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    I've got 7.8 6H in a C7500. No real issues, and certainly far less than my 3126 and C7 motors, by a long shot.

    And quite a few 6H in machinery, again, not very problematic.
     
  13. WaterDoc

    WaterDoc Well-Known Member

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    Head gaskets, turbo's and injectors for almost every 7.8L that we sold. Noisy and gutless, but the chassis wouldn't rust out thanks to all the oil leaks.

    The 3126's on the other hand had the occasional oil cooler or Heui line leaks or injectors now and then. The higher mileage ones would need water pumps, but that's nothing unusual.