Yes it definitely still has an unsealed leak. Not sure how to proceed but I would check/tighten every external connection in the cooling system & after that the heads may need to be pulled to get at the head gaskets EDIT before pulling the heads you may need to fill it with coolant & fire it up & draw some of the air above the coolant level under the rad cap with the "blok check" kit & see if it turns the fluid from blue to yellow which indicates the presence of combustion gasses in the coolant mix or if you have an emissions testing station nearby if you can persuade them to stick the probe in the air under the cap & the machine will detect combustion gasses if present in seconds.