I have an 02 that has a similar problem did you ever come up with an answer as to why it overheated????First off I have an 02, and an 03 PT cruiser and I'm a fairly knowledgeable person as far as cruisers and cars in general. With that said, my 03 that I just bought (used from an old man with pt never gets drove syndrome lol) started overheating not even a week after I bought it. The previous owner said he had just replaced the water pump but the signs pointed at the pump. You filled the radiator up and when it got overtemp (not over heated) I would let it cool down and check and there was nothing above the thermostat....I figured 1 in a million bad new pump. put in new pump...stilll over heating. changed cap...still overheating. Finally I said well I'll take the thermostat completely out (I had already changed it).....and now I have found water is magically disappearing. I fill it up everyday, and it runs below temp. No leaks around head. No smoke (steam) out the exhaust. Only weird thing is when you shut the car off water bubbles into the overflow yet the temp is still below temp. Oh...and the fan works. So for my question....Does anyone think it's the radiator BC I really don't know at this point. Could a clogged radiator be the problem? Anyone else scratched there head as hard as me?