That is a drain for the A/C evaporator. It is normal for water to drain
there when the A/C is on. Are you sure it's coolant? Have you had to add any
coolant? Feel the stuff that hits the ground. If it is slippery between your
fingers, like oil, then it's most likely coolant. Yes, it can come out of
the A/C drain tube. The heater core is mounted next to the A/C evaporator
core on that car.
According to my records, your vehicle uses dex-cool coolant (Orange or
pink in color). This can sometimes look clear when it's on the ground.
A more likely source for a coolant leak on your car would be the intake
gaskets. The 3100 V-6 has had many problems with this. Have someone pressure
test the cooling system, and look for leaks.