again could be air and wasnt all bleed out, now after driving and topping it up it may be bleeding air out and getting better.
there is no harm in taking the pressure cap off the coolant bottle and sit the car till its up to temp, turn the heater on and and make sure the ground is level or at least the top of the bottle is the highest point of the cooling system.
and you may find some air coming out after about half an hour you should have all the air out and put the cap on and go for a drive.
hope that makes sense it would be easier to talk rather than type.