Engine died

So, I was driving the other night and my engine died. I discovered this small vacuum tube was disconnected. Now the engine runs but now there is this squeak.

1. What does that small tube do? Also, is it supposed to have a hose clamp? I bought the truck used so idk what the previous owner did.

2. Any idea of why it’s squeaking?

TIA.

 

Its almost impossible to diagnose that noise here from just a vid. You need to use the old stethoscope trick to narrow it down to a certain area or external part. Could be the water pump, the idler pulley, or something else. Use a long screwdriver or even a wooden dowel and place it near the suspect area and next to your ear to see if you can isolate the sound. Of course, be careful when doing this on a running engine.

 

You can take off the belt and run it momentarily to determine if it is internal or external as well.