what did it do before?my pump went bad[bearings] i put the new one on along with a therm,now after 5 min the gauge goes to about3/4 the way over then drasticly goes to where it should,between the hash and the "n".and remains there,i tried burping the system,i could have a bad thermostat. more power to you if yours doesnt get hot.how long have you driven it,did it ever get to the "n"