The other morning it was 17F. WRX had been parked all night. Started it up, let it run for a minute and then started driving 30-40 MPH. Had the radio on and within a minute of driving I heard a weird screeching from the engine compartment. Turned the radio down and about 30 seconds later it came back. The sound is hard to describe, but I thought the engine was seizing from the sound of it. No warning lights appeared on the dash and the car ran smoothly. The sound stopped after a few seconds and hasn't come back. Oil level is OK, belts seem fine. Has anyone else experienced this?