I just got a 2000 LS, the 3.9 model. It started overheating on me and leaking coolant by the drivers inner fender. I just replaced the thermostat last night and it seems to not be overheating now, but it is still leaking coolant out from the drivers inner fender. I also replaced the radiator drain plug because it had a crack in it and now it is also leaking out of the horizontal drain part a little as well. Could this just be a crack in the coolant tank? Any help would be great. Thanks

Yes, it's a crack in the coolant resevoir. It will show the leak on the ground just behind the driver's tire.