Hello my grandpa has an 06 pt cruiser n/a auto and it's been over heating. It's totally baffling everyone who looks at it. So I figured this is a job for the td forum. He had a water pump put in . He had the coolant system flushed and a thermostat put in and it still over heats! Now it only over heats on hot days or in traffic. While driving the car will stay cool. I can't figure it out. Any help would be appreciated !!!!!