Coolant Reservoir

[Ped]

Hi, I am a little baffled by the coolant tank/reservoir. In that I can understand how/why it gathers coolant from the top of the radiator and stores it in the tank. But just realised that the bottom of the tank is blocked off with a blank rubber. So how does it re-enter the cooling system? and am i supposed to feed additional coolant into the system via the Rad cap?

Found this diagram. Honda accord but still applicable. Cannot fathem lol.

 

[spanner_monkey]

The coolant is all stored in the rad, yes coolant is poured into, via the rad cap.

The other bottle is just the expansion tank, it isn't pressurised.

---
I am here: http://maps.google.com/maps?ll=51.312253,0.888421