Just went through this with mine. With the engine bay pans in place underneath, it is often hard to determine where the leak is coming from. the coolant drips down on the pan and accumulates there until the pan overflows, so leak then appears on the ground, but perhaps not in relation to the source.
With my recent experience, there was fluid on the ground everytime the car was shut down and the engine cooled of. Common sources of leaks under these circumstances include, loose hose clamps, leaking water pump, leaking radiator drain, cracked coolant reservoir. The easiest way to locate the problem, in my experience is to have the coolant system pressurized. When I did this with my car recently, I discovered a crack at the nipple that the coolant hose to the reservoir is connected to and a leaking water pump. I installed a new pump, and a new coolant reservoir, tightened all of the hose clamps and pressure tested it again. I still have a very slight seep, not even a true leak, on the radiator tank. I'll watch it, I don't think it is significant enough of a leak to require a radiator replacement.
There are two other possibilities, the heater control valve and the heater core. Most of the time when the heater core starts to leak you will find coolant in the passengers seat foot well, but not always. When my heater core failed last year the bulk of the coolant leaked outside of the car.
As long as there is sufficient coolant in the car to fill the radiator and the water galleries in the engine the operating temperature will remain normal.
