1997 Chevy Cavalier still leaking antifreeze!!

I have a 1997 chevy cavalier, it was leaking antifreeze from the front of the car on the drivers side. The mechanic said it needed a new radiator. He put the new radiator in,, and i am still having antifreeze leaking. He tells me this is the excess from the old one he took out.. and its to be expected till it dries up... Its been a few days and its still leaking I am worried that its something else.. What else could be causing the antifreeze to still leak after a new radiator is put in??? The mechanic did a pressurized test and it showed that the radiator is good. no holes. So then where is this coming from... It happens when my car is sitting for awhile. Especially overnite when i wake up in the morning there is a decent area of antifreeze on the ground, drivers side front area. Estella