Ok changing coolant but unsure on getting air or the system. Looking online there is some sort of coolant bleed screw for this, but i cannot locate it. So is it a case of running the engine with the red cap off, topping up as and when? Is there any easy or more complete way of emptying the coolant other than the rad bleed screw, as i always find there is always a large amount on the cooling system (heater matrix i guess). And finally what coolant, pink green blue, silicon free, is there any special type?