[Jeff]

My heat/ac blower has been making a strange noise this winter, and I hope it's not a sign that it's going south on me. It only happens for the first 5 or 10 minutes after I start the Rav when cold (such as in the morning) and goes away as the Rav4 warms up. It's a strange scraping/rattling noise that sounds like the bearings are going. I thought it might be the various nuts and bolts I have dropped down the vents at one time or another bouncing around in the blower, however the noise goes away after the blower has been running for a few minutes. It also seems to be linked to temperature, because the noise only started when winter rolled around, and it gets worse as the temp gets colder, much like the grinding noise the starter makes. The blower didn't make this noise last winter, so I'm thinking that it might be dying, or in need of lubrication.

 

[Oil Burner]

I had a VW Transporter that did that every cold morning for five years, as far as I know it is still doing that to the new owner. Sounds like a dry bearing, you might want to try to get a little oil or grease in to the bearings, though I fear that it may be easier said than done

 

[noodlerooney]

Have you taken a look see at the blower via removing the filter?
I just did that with mine and found a damn mouse has been living on top of the filter along with all his acorns, wife, kids, in-laws, etc. Try running the blower with the filter removed while observing it's operation. Using a " magnet on a stick", you can probably retrieve a lot of those nuts and bolts you've lost without disassembling the unit. I'm really disappointed that a mouse is able to enter the cabin via the HVAC system. Placed a wire screen under the filter so he can't get in the cabin, replaced the filter with polyurethane foam for air conditioners cut to fit, set glue trap in place.