Within the last few months my mustang had been giving me problems about overheating, it would only overheat after about an hours worth of use on the car. Today I decided to finally change the thermostat. I drove it to the gas station & immediately noticed a puddle of coolant under the car. I went home immediately and checked the housing unit to see that it was leaking. I took off the housing unit & cleaned off all the old gasket residue. I waited about 30 minutes for the sealant to dry before I started the car again. After checking again the leaking had stopped & everything seemed fine. I took it for a test drive & the car started to overheat after a few minutes. I began to lose power in the car also. I drove it back home and filled the radiator with coolant as well. The car is still overheating. Im still very new to cars but I am slowly learning. I do not want to pay a shop to fix it so I would like to fix it myself. Note: The car ran perfectly fine before swapping the thermostat. ALSO I didnt test the new thermostat before installation. (Noob Issues). If ANYONE has an idea how to fix this please let me know. I ned this car for everyday use. The car is an 02 3.6L.