I noticed a puddle of coolant under my '96 today. It was still dripping a little after the car had been sitting for more than an hour. It was coming from the drain tube. I did not have the ac on today but the defroster was on for a short time. I am thinking maybe it could be the heater core although there has been no antifreeze smell in the car and there has been no moisture on the floors. For about two months now, I have been adding about a 1/2 pint of water a week in the radiator but could never find a visible water leak. Can this be anything other than a leaking heater core?

 

im not sure what exactly it is but a pressure check will be helpful.

 

Could be any possible things.

 

If you are speaking of the heater case drain tube which exits the firewall, then you've only got two sourses for fluid.
1) Coolant (Heater Core)
2) Condensation (from a cold Evaporator Core).

Now, IF you're ABSOLUTELY sure that the A/C hasn't been on*... that only leaves the Heater Core.
Congratulations!

P

*You did mention that you had the front defroster on (which works best with the A/C on.........