07 S80 V8 Coolant Issue

[Axinio]

Hello. My first post here. Just got an 07 S80 V8. It’s in great shape but has a few issues. One of which is when the engine is running, even cold, coolant flows through bleed/overflow lines into the overflow tank. The flow increases with the rpm’s. I thought maybe a head gasket but no misfiring, smoke or coolant in the oil. Coolant seems to slowly disappear though. Any thoughts?

Thanks