Vehicle is a '95 Toyota Corolla.
Was driving yesterday for about 5 minutes and glanced at the temperature gauge which I noticed was running pretty high (weather has been around 90 degrees f lately). As I was watching it pushed into the red so I immediately pulled over and turned off the car.
Opened the hood, no steam or smoke which I assume is good, but looked at my coolant tank and saw that it was bone dry. Left the car overnight and came back in the morning with more coolant, filled it to the fill line and drove home, about 1 mile, and everything seemed to be alright.
Today I wanted to test it some more so I checked the coolant and seeing that it was still at the fill line I drove about 4 miles and it started overheating again, so I pull over and turn off the car immediately.
I check the tank again and the coolant is still at the fill line. I walk away to call a friend for a ride and look at it again 2 minutes later and the level of coolant has dropped to about a quarter, and a small, fresh puddle is visible underneath the car.
My conclusion is that it was obviously a leak, but a buddy says it might be my thermostat acting up, because of the odd behavior of the coolant.
I wanted to get a second opinion so please let me know if you need any other info. Some additional things that might be helpful are I didn't see any coolant in the oil when I checked, and I also didn't open the radiator cap to check for coolant since the car was hot, but I will check that soonish.