Coolant Hose Popped Off the Thermostat

[legozombie]

So I'm here in Colorado and just experienced the winter storm Anya. I'm not too familiar with engine cooling systems so I'm not sure what happened.

I had my truck running with the defroster on full blast while I shoveled snow (so idling for about 15-20 minutes?). I was on my way to drive it around and smelled something funky and saw some smoke behind me as I drove off. Thinking it was just condensation or whatever I went a couple of blocks and noticed smoke coming through the firewall. I pulled over, popped the hood, and noticed that the upper radiator hose was off and everything was covered in green coolant. The hose clamp was tight and the radiator was not compromised. What could have caused the pressure to build up and pop the upper radiator hose off the thermostat?

 

[legozombie]

After installing a tachometer today, I was idling around 200 RPM or so when my truck was idling with the defrost on. Could it be that the water pump wasn't able to move the fluid around at such low RPMs and then caused a pressure build up?

How do I test if my water pump is failing?

I think some coolant may have gotten in my carburetor since I forgot to put back the air cleaner from the last time I touched it. How screwed am I? It still runs and drives.

 

[Robert Bare]

I doubt you could get a small block to idle that low.
Sounds like coolant was partially frozen. Or maybe clamp was not tight enough.

 

[legozombie]

I'll double check the tachometer to make sure I have the setting for v8 setting.

 

[77Dmax]

I wouldn't over think this one. Replacing radiator hoses used to be very common. I would replace the hose and move on.

 

[legozombie]

I appreciate the advice, I was lucky I pulled off before I left my neighborhood. I refilled the coolant yesterday and it took 2 gallons of coolant 50/50 to fill back up. I still need to take my gauge cluster off and fix my engine temp gauge needle so if it happens again, I can keep a better eye on it. The needle was brittle and fell apart lol. My biggest fear is it happens on the highway and I have to get it towed.

 

[legozombie]

I'll double check the tachometer to make sure I have the setting for v8 setting.

It was on the v8 setting so idk what to say regarding the 200 rpm I saw. It was definitely below the 500 mark.

 

[75gmck25]

First thing I’d do is to replace the radiator cap. If the pressure release is bad it might let it get too high. I think the stock cap is rated at about 16 lbs pressure for most SBC’s. Also make sure it pushes coolant into the overflow when hot, and then draws it back in as the engine goes cold.

I had challenges finding the correct sending unit for my ‘75 (GM discontinued the original), so I was not positive the gauge reading was always right. I finally added a mechanical temp gauge from Summit and used the threaded hole in the passenger side to install it. It’s a simple way to keep an eye on engine temp.