[tiggertsi]

i've experienced the same problem after changing my water pump and radiator. water pump was bad. the radiator became bad when i tried to remove the hose from the top the plastic just fell apart. and in my case it was air pockets. i had to bleed the system a few times before the temp gauge would stay consistent. and that was over a week of driving it back and forwards to work, etc.

i'd advise bleeding it more maybe over a week and watching what the temp gauge does. if it continues after a few bleeds you may want to look into something else.