Tiger28, just a word with the above method, it's also recommended to throw in some "Radiator Stop Leak" (what mechanic shops call neutralizing the system). That stuff is like rat pellets in an oily substance. If the coolant doesn't have a certain property (can't remember the name off the top of my head) the coolant can actually start eating through the aluminium parts, and VERY quickly!
With your overflow reservoir, it might just be easier to take off the neck and undo the screws underneath and clean it out properly... flush it with water a few times.
Also, just for people that read this, on the V6's there is just one bleed screw, however with the Supercharged engines there is 3 bleed screws over the engine. I have posted the correct procedure for supercharged vehicles too, so if you are wondering, search of pm me.
