Check the hoses associated with the overflow tank. Also, check the level to make sure it's not overfilled. While there, verify someone didn't use a screw that was too long to secure the belly pan and wound up puncturing or cracking the tank. How does your radiator cap look? Inspect the weep hole under the water pump. It is very close to the exhaust pipe so if it's only leaking when running, the drip may be hitting the hot pipe. Good luck.