Barry is right; I'm more inclined towards a crack or bad HG than a simple leak. I haven't seen any external leaking/steaming even with the engine hot and the system under pressure.
So I'm going with the waterglass option from Rislone.
I realized I forgot to share the snapshot of the oil analysis results.
https://www.dropbox.com/s/11pypszrl1yh0y9/Oil_Sample.png
I hope you guys can see it.
Thanks,
Tudor
PS - I'll post an update as soon as I've tried the sealant.