Thanks for the useful info James/Neil/Malcolm. Reason I'm asking is that I just installed a new radiator (only paid $315 if you can believe it - a Behr too). Installation went surprisingly quick. Anyway, there will be lot of air in there to start with, so if you say it's self bleeding I hope you're right. Is there a definitive answer to the bleed screw question? Just want to be sure. Thanks again.