2006 PT cruiser overheating

2006 PT overheated a year ago, not to the point of the red line but it was
steaming. Towed to shop. Themostat installed. Now one year later it is over-
heating again. Took it to same shop. They think it is the head gasket but they
don't do that kind of work so referred me to another auto shop. Took it there.
Did compression test not head gasket and see no problem. Flushed out
system. Added new coolant. $130. 5 days later overheating again. I stop
before it red lines.   Installed new radiator and another thermostat. $684.00.
Two weeks later, still overheating. Take it back. Install new fan and radiator
cap (I just replaced the cap a month ago.). $334.00. I drive it two days. Pop
the hood just to look. Very hot. Reservoir is slam full of coolant. Check it next
day, reservoir still full within one inch of top. So now I am in the hole over
$1100 plus two two bills. It did not overheat after putting in the fan but I am
concerned as to why the reservoir is so full. I have a new car but I drive 75
miles round trip to work and am trying to keep miles off it. I bought PT new
and it has been excellent up until now with very minor issues. But boy is it
making up for it now. I would be interested in hearing back with any ideas. I
am a 64 yo lady so I cannot do the repairs myself. Both of these companies
are very reputable in this small town that I live in.