My engine has been over heating very quickly when I go down the highway. I have checked the thermostat and have pulled the water pump out and it seems fine, I mean the shaft turns and the impeller turns. i put the thermostat in a pot of water and slowly brought the temp up and watched it open and used a temp sensor to see when it opened and that was about 185 degrees. I put all new antifreeze back in it and the is no fluid leaking into the crank case. The timing belt does squeal at startup sometimes.
the year of the car is 1998 and it has 225,000 miles