2003 Honda Accord EX V6 182k

An oddity I noticed... the radiator overflow tank never seems to have ANYTHING in it at all (not even the minimum level) but since the only fill is the normal radiator fill cap that I can tell, and that is always absolutely full to the brim, I can't figure out how i'm supposed to add anything to make the overflow tank even be at the minimum...

Should I be concerned?

 

Your overflow should have a cap and a full line (the cap should have a small hose coming from it to the radiator. Take the cap off and fill it to the fill line.