I recently had the radiator and thermostat replaced. The shop had to replace the thermostat twice because the first one was defective. When I got the car back it was fine. No overheating and plenty of heat in the cabin. After about 3 days, the car started overheating again. I stopped and was able to make it to a safe place a few minutes later. I let the engine cool, and then proceeded to bleed the air out. I found that the level in the radiator was low and the overflow bottle had a significant amount of coolant in it. It was not draining back into the radiator. After bleeding the air out, I made it home with no incident. The car was fine again.