Strange water knocking sound.

Discussion in 'Tech Discussion' started by Dutch Rutter, Dec 4, 2018.

  1. Dutch Rutter

    Dutch Rutter Full Access Member

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    Location:
    Jefferson, Or
    First Name:
    Joshua
    Truck Year:
    1984
    Truck Model:
    K20
    Engine Size:
    5.7
    Recently I replaced my water pump, and clutch fan with new severe duty units, I also replaced my radiator with a new unit. Have been driving it just fine without any heat/cooling issues what so ever. Except after I shut the engine off I hear a knocking type of sound. I opened the hood to see my upper radiator hose bounce along with the knock.

    First I thought an air bubble so I did the burp process, no difference. Then thought air bubble trapped under the t-stat, so I pulled the 195 out and drilled a single 1/8" hole in the flange and put it back, re did the burp process. Still getting the knock sound along with a "boiling feeling" from the upper hose if I squeeze it a little when its cooling down.

    Temps are all still fine, coolant seems to be flowing like it should, overflow bottle works like it should, heater is fine, no visible leaks.

    Today I ordered two new t-stats a regular flow 195, and a high flow 195 without bypass holes as a shot in the dark but I have no idea if they'll help any. Any thoughts on this?
     
  2. Charlie

    Charlie Full Access Member

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    Truck Year:
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    Cheyenne 10 LWB
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    350/TH350/AC/4 BBL Quadrajet
    Try a new radiator cap. I have had issues with some.
     
  3. Dutch Rutter

    Dutch Rutter Full Access Member

    Age:
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    Joined:
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    Location:
    Jefferson, Or
    First Name:
    Joshua
    Truck Year:
    1984
    Truck Model:
    K20
    Engine Size:
    5.7
    Thanks for the recommendation but I forgot to mention, I did get a new cap and it seems to be working well. I'll grab one of those pressure tester setups and give things a go over as well just to make sure things check out.
     

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