The car has been giving me a Low Fluid Low level warning
(sound and buzzer). I have checked the sensor located on top of the radiator.
While the sensor tests good, I have found that the fluid level above the
radiator is low indicating that the sensor is working too. I have bled the
system twice and even filled the area above the radiator with fluid using
the port that the sensor is mounted. The problem appears to be that the
fluid is not being drawn back into the radiator system overflow container as
the coolant cools. I have also checked the overflow hose from the radiator
cap to the overflow bottle and all appears ok. The car isn't overheating despite the hot weather in the Chicago area in the last couple of days.

Any trouble shooting suggestions and/or anyone having similar problems?

 

what do you mean by "area above the rad"?

You mean the water pump?

 

The area within the radiator didn't have coolant in it when I removed the sensor at the top of the radiator. So it appears that coolant is flowing into the overfill bottle but not flowing back into the radiator.

 

Check that the two hoses on the lid of the expansion bottle are hooked to the correct spots. Look very carefully, the geometry of the cap is weird. The one that comes from the radiator should go to the hose that runs to the bottom of the expansion bottle, and the overflow hose should go to the little baffeled hole in the cap. If they're on wrong the water will go out but won't be sucked back in.