Check the state of your hoses as they'll be 15+ years now if they're originals and may be starting to degrade, and harden then crack.
When refilling I always find that squashing the hoses in and out of the radiator helps to squeeze out the air bubbles and get the coolant moving around a bit before running up!
I'd rather die peacefully in my sleep like my Grandfather, than screaming in terror like his passengers.- Jim Harkins