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Upper Radiator Hose has no pressure

Discussion in 'Engine & Performance' started by ceejay, May 11, 2020.

  1. ceejay

    ceejay Junior Member

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    I'm working on fixing my 81 C10 I bought, and I'm at the point of engine cooling. I went ahead and threw a new thermostat on (AcDelco 195) and radiator cap (AcDelco), And I drained the radiator, filled with water, and after getting up to temp, still no pressure in upper radiator hose. Temp gauge shows a little before middle point (don't really know how accurate it is). What do you guys think?
     
  2. Dutch Rutter

    Dutch Rutter Full Access Member

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    Did you happen to boil the new t-stat before install to make sure it opens? Also the system could need burped to get the air pockets and such out.

    Newer t-stats have a small hole in the flat portion to help air flow through it and not get trapped underneath the t-stat. Some drill a very small hole in their t-stats for this purpose.
     
    Last edited: May 12, 2020
    JTWard and 82sbshortbed like this.
  3. ceejay

    ceejay Junior Member

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    I ran the truck for a little bit with the cap off and it seemed like most of the air got out. I didn't try to boil the thermostat, I guess I just trusted it being a ACDelco. I can try taking it off tomorrow and boiling it to eliminate that possibility.
     
  4. nabeshin

    nabeshin functioning lunatic

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    Did you squeeze the upper hose a lot with the cap off at temp?
     
  5. AuroraGirl

    AuroraGirl Supporting Member Supporting Member

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    Is the thermostat the right direction. Did you bleed air from the system when putting coolant in. Did you put coolant in the radiator.
     
  6. Dutch Rutter

    Dutch Rutter Full Access Member

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    Some are hit and miss anymore. Always a good way to check is the boil method. Something else to look at before that though. How are the hoses ran to the engine? And water pump? I tried switching one of mine once think it'd be a cleaner run but put an in to an out or something like that and it caused zero water to be flowing. Also how old is the water pump? Possible it gave up the ghost.

    Several different possibilities.
     
  7. ceejay

    ceejay Junior Member

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    So a little update, I ran it again this morning. I let it get up (or what I thought) was up to temp, and still no pressure. I did it without the radiator cap on as well.

    I attached some pictures of me squeezing the radiator hose and it's effect as I was doing it at the radiator cap location.

    Temperature gauge never got higher than what is pictured as well.

    Have not tested thermostat yet, was hoping getting up to temp again and squeezing the hose would get some coolant up there, but no avail. When it cools down I'll test it.

    IMG_20200512_084953.jpg

    IMG_20200512_085445.jpg

    IMG_20200512_085012.jpg

    IMG_20200512_085458.jpg
     
  8. Termite_Delight

    Termite_Delight Full Access Member

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    I don't think you are getting it up to temperature... Your temp gauge should be past 1/2 with a 195 deg t-stat.
    Take it for a drive, get it hot.
     
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  9. ceejay

    ceejay Junior Member

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    I guess I was skeptical about the gauge because it ran for about 20-25 minutes and that's how far the gauge got.
     
  10. AuroraGirl

    AuroraGirl Supporting Member Supporting Member

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    Thats about where my gauge runs on the cooler side, probably 180 or so. Then maybe a little further when closer to 200. My hose also looked like that when it was BAD and the pressure collapsed it like that, even with no air. I vote new radiator hose.
     
  11. AuroraGirl

    AuroraGirl Supporting Member Supporting Member

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    Thise hose # shown has been great and its a gates. When I replaced the hose it no longer looked like it squished down, as if it has no pressure. If your hose and radiator werent working right it would have overheated and you would know it.

    20200211_112503.jpg
     
  12. 82sbshortbed

    82sbshortbed Get outta there! Supporting Member

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    It won't build pressure with cap off. Idling for almost a half hour your motor should have overheated if the t stat wasn't opening up. But, as said take it for a drive so you know it's good and hot.
     
  13. nabeshin

    nabeshin functioning lunatic

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    When I tackled the cooling system, I also replaced the temp sensor in the cylinder head. It was all covered in scale, the gauge would only show about 1/4 like yours. Maybe you can take that out and clean it off, or replace it. I also got a new pump, thermostat, all new hoses, and a rebuilt radiator. With a 195 thermostat, my gauge is dead nuts on center when fully warmed up.
     
  14. dvdswan

    dvdswan Full Access Member

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    Silly question, did you crank the heater on high and run the air out of those lines as well? BTW, I would replace the heater hoses too. The one on the w/p is looking a little peeked and tired.
     
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  15. ceejay

    ceejay Junior Member

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    I'm not even home right now, but are you guys saying it would be better to go ahead and replace the hoses? If so, I see the part number for the upper radiator hose (thanks @AuroraGirl ). Anyone have a good number for the lower? Id like to get one that is known to fit good. I'll probably run to the hardware store and get tubing for the heater hoses. Still haven't tested the thermostat. Temp sensor (in between 2 spark plugs) I took off but put it back on because I couldn't find one locally (I started a thread about that, attached is the pic of it)

    IMG_20200504_073858.jpg
     

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