overheating, ? Options

[jayi12-15psi]

Lately my engine has been running warm, it's not getting too hot, just almost to the top of the little temp. emblem(as opposed to being on the little wavy line). I replaced the radiator in august, and it started doing this a few months later, so I took it to a mechanic. The mechanic found a small leak when he pressure tested the system(it was a hose he tightened it, and filled the radiator back up with coolent). Then about a weak later it started doing it again. I seem to be losing a small amount of coolent, is it possible for coolent to somehow disapeer in a pressure tight system? Because I can't seem to find a leak.

Thanks for listening.

[Coomer]

If a couple cups worth of coolant is disappearing per week and you can't find a leak, I'd guess that it may be your head gasket. I'd see how your oil looks.