Doesnt it cause a problem if there is such a big air pocket? Not sure wit the micra but I know with a few cars that I've owed that if you don't bleed the air pockets out of the cooling system it causes the car to act a lil funny.
Just looking for a radiator cos I just brought a micra & the top tank is cracked.
Hopefully someone in Sydney has one or if someone is willing to post.
Cheers.