My 24 year old gas furnace makes a slight noise when the fan first spools up, nothing real serious sounding and it's been doing it for quite a few years. After 3-4 seconds the noise goes away once it reaches speed. I went down to check it out and on the motor housing behind the bottom panel it has a sticker with an oiling schedule for motors with oiling ports on them. I did a search on this and saw on youtube etc. that oiling ports are typically on top of the motor. With the bottom panel off I felt inside on top of the motor (I can't see in there) and could feel no caps for the oil ports. Is it possible this motor has a sealed unit and does not need oiling? Should I pull the blower assembly out and take a closer look? I've never had it out before and it looks like I'd be removing some electrical parts etc. but it does look doable.