New here, Got a problem with my XD!

[AK's in my XD]

Hey everyone,

I've had my XD since mid '07. It's a '08 model (pretty fun driving it around when no one else had one). Within the past few years, every winter (California winter, that is) my XD starts making some noises I don't care to hear. The first time it happened I ignored it, and after some time, the serpentine belt busted and took the water pump with it. The next winter I took it to a "trusted" mechanic who told me the belt got loose and needed some tightening? If you couldn't tell by now, I don't know much about this stuff. The following winter I took it to Toyota, who asked to keep the car over night to make sure they started it nice and cold. Their experiment came with no results (but no noise after...).

This year when the cold weather started and brought the noise I decided to make some notes...

The noise occurs around 2500 rpm. Especially when the auto tranny shifts gears.

If I give the car plenty of warm up time, the sound is significantly lees apparent, yet still present.

After a few trips in the car, the noise is gone.

Does anyone know what's going on? Please pardon my lack of info, but I'd be glad to give more pending inquiries.

Thanks everyone!