Arrived onsite to investigate a noise coming from an oil-fired furnace. Upon arrival, the furnace was running and the noise was audible upstairs. After inspecting the unit in the basement, I confirmed the noise was coming from the supply fan. Further inspection revealed a loose belt and a dead mouse in the squirrel cage. I tensioned the belt and removed the mouse. The supply fan then operated normally. Verified operation, and the system is working properly at this time.
