Several issues to address: Belt that runs my ac compressor is off the pulley but dont know if it effected the cooling issue. Was driving yesterday and temp gauge began to rise towards the top. Pulled over and the radiator overflow was blowing coolant out. I let it cool off and the temperature fell. Any suggestions on what might be the problem. As far as my knowledge goes, I believe it could have been a sticky thermostat, air bubble or block in the cooling system. The water pump was not leaking fluid so I think that is in good shape. Could the belt that runs the AC be effecting anything with the cooling system?