A Leaking coolant tank is not a good thing. Verify if it is and replace it if needed. My problem was a leaking head gasket. After the engine warms up, check the exhaust pipe for a small amount of water coming out . Not having the money for a mechanic to change it out, I used "Blue Devil pour n'go treatment" 32.00 a bottle, but well worth it. Follow the directions as shown. My PT no longer overheats. Was sounding like a coffee pot boiling all the time.
If it works. Be sure to actually replace the head gasket eventually.
Also, make sure"Both" speeds of your fan are working. There is a low speed and a high speed. When the high speed comes on, you can really hear it! The fan should stay on after you turn off the key for awhile. Cools the water in the radiator. If not have your sensors checked. Good Luck!