Hi SSage,
if you get a hose to fit the nozzle of the pump and a 2 liter soda bottle you can prime the pump
simply drill a hole slightly smaller than the hose in the cap of the 2 liter bottle, and force the hose into the cap about an inch or so
fill up the 2 liter with water or coolant mix cap it with the new hose creation and attach the free end of the hose to the nozzle
invert the 2 liter bottle and let the coolant flow for a few seconds until the bubbles disappear
then switch on the coolant pump for a second or 2, be ready to switch it off quickly!!!!
if the pump starts to fill the 2 liter, it is primed
if the 2 liter trick doesn't do the trick, goto troubleshooting the pump
worn pump shafts and/or worn seals can introduce air into the suction side of the pump.
a split hose, a loose hoseclamp, a pinhole in a fitting or hose could cause loss of the ability to prime itself anywhere in the suction side of the system.
any hardware responsible for holding split pump housings/castings are suspect for leakage.
that's what i got right off the top of my head
maybe worth a try