Could someone please help me. I have a 98 Legacy sedan GT. The main pulley has started to slip off the harmonic balancer, so I replaced it. On the test drive it overheated and that's when the fun began. I pulled off the front engine cover and there was no damage. Put on new thermostat. Radiator is only 3k miles old. New timing blet and tensioner from previous repair. I know about the famous head gaskets, but the car doesn't smoke, no oil in coolant or coolant in oil, and no coolant leaks. The weird thing is the car will run at idle for hours with no problems. It will even drive for a few miles before overheating. I am stumped. Could it still be the head gasket or is there something I missed. Has anyone else had this problem? Please Help me. Thanks.