Where does this hose go?

I found this hose blocked up from the “Monifold tank” but some peole call is the Expansion tank/header.
I cannot see where it is supposed to go.
Can someone tell me where it is upposed to go.

Maybe there is something missing here that this hose connects to?
Anyone know?

Michael.

This is my spare rad, somebody has broken off the spigot that that hose fits onto, you can tap the header tank and insert a tail piece in there, I had to do that to my car when the mechanic I employed managed to break off the plastic spigot

This is a sample of the tail piece;

Thanks.
I will need to get another rad if I cannot fix the leak. At least I know where the pipe now goes.

Thank you for clearing that up.
Michael.