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.

[jAzn95GT]

Well, from previous experience, i once own a 1988 celica and i kept having this same problem of overheating. I change the thermostat and still, same o' problem. so i talk to a couple of my friends about this and they said the way they "solve" this problem was by putting a "manual switch" connecting to the wire from the thermostat. with this, whenever the temp guage is above normal, i would turn the switch on that will then turn on the cooling fan to cool the radiator down. It work. But i'm not really sure if it's the case with your celica. I'm thinking that there may be a bad circuit between the thermostat and the fan that should cool down the radiator or engine when it begins to overheat.