So the other day I was walking to my car after work and hit the auto-start to give the car an extra 30 seconds or so to warm up (it's already in the 30s in MN). As I approached, I heard a horrible ticking noise that was so loud I shut the car back off before I got to it. After popping the hood and trying to find an obvious culprit, such as a squirrel stuck in something, I could only tell that the serpentine belt was vibrating really badly.
Despite the noise I drove it home and then straight to the local shop. They found a rock lodged in the AC pulley. I have no idea how that got there between the time I shut my car off upon arrival and starting the car when I left work but somehow it happened.
I took off the big plastic splash gaurd a couple days ago to look around which probably was the only reason a rock found it's way up in there. Lesson learned.
