Simplifying The Coolant System?

[brainbug007]

Ok that makes sense, I'm still confused then how I get round only having 2 connections on the radiator instead of 3 (1 in & 1 out). If I've got the out going hose connected to the water pump and thermostat (via a loop which would have had the heater), and then the outlet of the thermostat going to the top inlet on the radiator, where do I put the bottom pipe of the expansion tank? Do I just add another T piece to the radiator inlet for it?