The cooling fan makes a chattering sound, like something hitting the blades. Upon inspection I did not see anything blocking the blades. Problem started 1 day ago when air temp reached 102 degrees. Car was warm but was being driven a speeds not exceeding 40 mph. The temp gage was very high. There was no water leaks to be seen. Coolant level was in range. Checked fan blades today, they spin ok with power off.