Without hearing the noise myself, my guess would be a worn watts link bellcrank.
It seems to be the most common source of PT rear suspension metallic sounding noises.

 

Elaine, if you're going to attempt to repair it yourself, I would recommend the purchase of a set of chassis ears. (Amazon.com: Chassis Ear Automotive Engine Noise Finder Tool, 6 Channel Chassis Ears Sound Detector Identify the Troubling Engine Noises (Over-Ear Headphones) : Electronics) They will be instrumental in locating the source of the sound. Attach the ears to parts of the chassis and slowly rule them out one at a time while someone else drives the car for you. I've used the set I've linked several times to pin down troublesome noises. If you've got the bucks, the wireless set is much more convenient, but as a DIYer I couldn't justify the additional cost myself.

If you're not working on it yourself, I would caution against soliciting guesses. This sort of problem has many causes, and telling the mechanic what to look at can be truly counter-productive. Take it in and let the mechanic find and fix it.

 

The lady asked for any ideas. Just replaced my 3rd bellcrank...thought it might be a good place to start for someone qualified to look see.

 

I'm with Carl on this one. This is a well documented issue with the PT Cruiser.

 

If there is even the slightest bit of play in that bellcrank it can be easily overlooked yet make a helluva racket.

Otherwise, there are lots of other suspension components that can go bad and get noisy.
It takes patience along with a trained eye and ear to track these down.