when bleeding the cooling system, put the interior heater to hot and full blast, open up radiator top bleeder or cap and fill up, start the engine. keep the interior heater on, so it forces all air out of the heater system. if running system is pushing out water/coolant out of radiator cap, stop the car and fill it up, compress the upper pipe from engine to radiator many times to get the bubbles out, fill more until no air comes out. reapeat many times until you see no air. put on radiator cap and fil the overflow tank to half-full. check for radiator leaks, maybe you need to replace the radiator.

plain water in radiator will make the car overheat much faster, when you`re standing in a traffic jam or just leaving the engine running. water has much lower boiling point than coolant. when the water reaches 100C degrees it boils and evaporates thus creating air pockets in the cooling system. then the pressure gets terribly bad and if not revving(thus taking away the air pocket from engine) then the pressure just blows your radiator in pieces..this is what happened to me - did 7min drifting in hangar, then after stopping it took 5 seconds to build up air bubbles in system and blow the radiator in pieces.

other problem with water - it creates rust in the engine. you can easily mix water/coolant in 50:50 proportions. but if heat problems appear, just replace the water pump, fill up cooland and drive happily :)

engine cooling is a serious factor in 3sgte performance or failure.