A common cause for overheating in the 2001-2002 PT Cruisers is a clogged radiator. One way to check for this problem is by shutting off the engine after the vehicle is warm. If the center of the radiator is cool but the edges are warm, a replacement radiator is required.
A second method of diagnosing this problem is to feel the air coming off the radiator when the engine is overheating and the fan is blowing. Because of the clog, the coolant does not flow through the radiator, and the air remains relatively cool. The problem is due to a faulty engineering design that calls for tubes inside the radiator coil that are too small, which lead to clogs.