My 1994 3000 GT SL starts to overheat when I idle for an extended period of time

It gets cooler once I start driving. My car doesn't quite get to the overheating point, but very close at times. I have replaced the cooling fan motor, thermostat, and water pump to no avail.

possibly a blockage in radiator which causes restricted coolant flow, then as you drive the water pump moves the water pump moves the coolant faster and it gets better

I was kind of leaning that way myself. One other thing that I noticed recently is the coolant level is reading at the high mark on my reservior tank, but my low coolant level light illuminates when I take sharp turns. If you have any other advice, please share. Thank you for taking time out of your day to assist me with this issue!