260Z - pipe & hoses from thermostat housing?

[MariaAZ]

I have a water leak on one of the hoses that comes out of a tube off the thermostat housing. There are three hoses on this tube; one comes straight out and goes to a line around the back of the engine (possibly to the heater?), and two come out the bottom of the pipe and appear to go into the intake manifold (it's hard to tell, I haven't pulled the hoses off yet to trace where they go.) Also, the hose that goes straight in looks like it's been blocked. When I pulled off the hose I found what looks to be a bolt screwed into the pipe then cut off.

I couldn't find reference to these hoses in neither my Clymers nor my Haynes manuals and was wondering what they are. Below is a picture, the part in question is the rusty discolored tube in center.

[fixitman]

The attachments should help you trace the coolant lines.

Fixitman

Carb Coolant Hoses.pdf

Carb Coolant Hoses2.pdf

[MariaAZ]

Thank you!