Collapsed upper radiator hose

[George915]

So I just installed my new engine in my 1984 K10. New rebuilt 350 stroked to 383. Started engine on run stand 2 weeks ago to make sure everything ran fine. Finally started up engine for first time today in truck annd engine ran fine. Ran for 45 minutes in driveway hoping to burp any air bubbles out. Temp never got past 180 to open thermostat. Ran again this evening hoping to get air out again same thing temp stayed below 180. Shut engine down and when I came back out later upper radiator hose was collapsed. Removed cap and hose expanded. Everything is brand new on engine. Cold case radiator tuff stuff performance supercool water pump tuffstuff 180 degree high flow thermostat. Any help would be appreciated.

 

[squaredeal91]

How is the radiator cap? New? Slightly newer used condition? Not likely but there are 2 different water pumps depending on if it's serpentine or v-belt. Both look the same but flow differently

 

[ChuckN]

I was gonna say, usually the lower hose has a spring in it to keep it from collapsing, so the fact that the upper is collapsing makes me wonder if it’s reverse flow? (Edit- meaning the water pump is reverse flow)

If it’s a Cold Case, you should have a new cap that came with it (mine did).

 

[PrairieDrifter]

Are the hoses new?

 

[Turbo4whl]

As stated, if the pressure cap is good, then there is still probably air in the cooling system. This is one of the reasons to drill a small hole in the thermostat, if it does not already have a vent. The vent insures that the cooling system is mostly full of coolant to start with.

 

[George915]

Like I said everything is brand new down to the hose clamps I double checked the pump I have a v belt system it is not reverse flow unless it was packaged wrong. looked up the thermostat it stated it is designed to allow trapped air in the system to escape. Unless it is not operating correctly. And yes the radiator and cap are brand new