[Froggo]

If you are getting coolant running from the tank overflow pipe it can only come from two sources , the cap or the bleeder valve .You can see both of these if you remove the cover plate below the coolant cap / oil filler cap , neither should leak .As JFP says the only sure fire way to bleed this system is to apply vacuum .If you have a compressor an Airlift vacuum bleeder is about $100 , if you don't I have used a Harbour Freight vacuum brake bleeder $10 and a rubber bung ,a bit slower but it worked ok. Utube the operation detail .I think you still have air in the system , the heater circuit can be the problem as the pipes are at the top of the core
Peter