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OBS Overheat!!!!

Discussion in '7.3L Powerstroke Diesels' started by Kraig, May 20, 2020.

  1. Kraig

    Kraig Full Access Member

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    Thank you for the info. That was very helpful. I am pulling the glow plugs today to check in that.
     
  2. Kraig

    Kraig Full Access Member

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    I just drove her for 3 hours yesterday and immediately upon returning home out it on a pressure tester. When I started it it did not immediately jump up the pressure. I sat there and revved it up to 2500 for about two or three minutes and the pressure rose to about 15 but no more. Thoughts?
     
  3. Kraig

    Kraig Full Access Member

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    Ok, I have some new theory that fits my symptoms.
    As many have said, injector cups could be the culprit. But I have not smelled fuel in the degas. That may be a fluke. Theory: cups leak the higher pressure fuel into the coolant system, it's full so the higher pressure makes the cap relieve blowing coolant out of the truck causing low coolant and rising operating temps. The only thing that doesn't fit is that I have not detected fuel in my coolant. But I have been getting worse fuel economy by a little. Sometimes I'll get 12 or so and normally it's 14-15. I just towed a heavy trailer and I got 9mpg.
    This seems to fit my symptoms. At least mostly.
     
  4. aggiediesel01

    aggiediesel01 Full Access Member

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    What did pulling the glowplugs reveal? DId any of the glowplugs look "steam cleaned"? Did you do a compression test at the same time by chance? That might help validate or alleviate concerns about a hydrolock issue. All that "blowby" in your video could be coolant steaming out of the crankcase. I pretty sure there's some test strips specifically for testing the coolant for combustion gasses, the 6.0 guys pretty much have to carry those in their glove boxes. I'm not sure why you're thinking about fuel in the coolant now that would be pretty odorific and it floats on top of the coolant so it would be visible pretty quickly in the reservoir. The injector cups are only located down at the bottom of the injector bore and are primarily responsible from sealing the coolant passages from the combustion chamber. The fuel galley is the next item above the injector cups but it is oring sealed at the bottom of the galley so I don't see how fuel could be getting to coolant unless the oring failed and cup was cracked? Go find the Coffee Table book for these powerstrokes b/c I'm pretty sure there was a cutaway picture of the head with the injector installed to see what is where. I think you should focus on combustion in the coolant more than fuel.
     
  5. greenskeeper

    greenskeeper Full Access Member

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    I'd still be on injector o-rings or cups. The problem is showing itself intermitently depending on how that o-ring or cup fails during the cold/hot cycle of driving the truck.
     
  6. Kraig

    Kraig Full Access Member

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    Well it was low on coolant yesterday, I got it up to temp to test the coolant for combustion gases, it then started to bubble significantly. Then coolant started bubbling out of the degas bottle. That happened for about a minute then it went back down, but as I said before, I did a combustion gas test and it showed very little if any combustion gas in the coolant. So it does seem the problem is intermittent and I have been running straight water for the last week or two so I don't know if fuel would show up in water as it does in coolant. I still suspect that fuel is getting into the coolant and causing the degas to relief.
     
  7. Kraig

    Kraig Full Access Member

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    But my stainless cups and injector Orings will be here his week so I will do that and do another coolant pressure test
     
  8. greenskeeper

    greenskeeper Full Access Member

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    fuel would settle to the top of the degas bottle....really obvious if it was that.
     
  9. greenskeeper

    greenskeeper Full Access Member

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    what source did you get the stainless cups? I'd only go OEM for cups if it was my truck.

    Another long shot is try tightening the injector hold bolt...I believe it is 10 ft/lbs but I've gone as tight as I can get with a 1/4 drive socket.

    Loose injectors are more common than you would think, not saying it could cause your issue but it's an easy check.
     
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  10. Kraig

    Kraig Full Access Member

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    I got them from riff raff diesel. I figured that was a reputable place. I will also be torquing the injectors down when I change the cups so that'll be checked.
     
  11. Kraig

    Kraig Full Access Member

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    I am cutting bait on the Injector cups after seeing the injector's uneven (or nonexistent) oil spirting and the blow by coming from the valve covers. I found a wrecked donor truck with 125k less on the clock and I can get the whole truck for a good price. And swap a few parts I need on my truck over too.
     
  12. Kraig

    Kraig Full Access Member

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    Well after seeing the amount of blow by and inconsistent oil flow of the j hectors under the valve cover I'm cutting bait on this engine. I am buying a whole wrecked truck from a guy I know with 125k less on the clock, freshly tested injectors, resealed oil cooler and almost no blow by. And ok getting the whole truck sk I can swap over any items I need for my truck too.

    any tips on things to check or change while the engine is out? I'm thinking of doing the ebpv delete, new turbo rebuild and 66/88 upgrade, and wither new or resealed down pipes
     

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