I need a little help guys. I think my electric fan is failing and I'm not sure where to start. It's hooked up on a temp-relay with a manual on and off. I've been leaving the relay to do it's job (got a 180 degree hooked up). When the fan activates and deactivates, there's a squeaking/scraping sound going on in the case of the fan. Airflow is also severly reduced. I haven't boiled over yet, but it's been a little scary in stop and go traffic. The casing seems tight still, the wiring is good, and it's getting power. Is the motor toast? What should I be looking for when I take it apart?