Found some rust on a part... what part is this, and is it a problem?
 

So I was working on my car, and I noticed some rust on a part, but I'm not really sure what the name of this part is. Can someone clue me in, and do you think it's something worth bringing up to Subaru while I'm already there for some other warranty work?

There's a little bit of surface rust on that bolt as well, but I'm not really concerned about that.

https://lh5.googleusercontent.com/-s...502_131646.jpg

That looks like part of the rear sub-frame, and it's not likely worth warranty work (not sure if they'll cover it, especially if they offered some kind of treatment you declined...) Worth asking, but it may be "that's normal."

Rust on suspension and stuff under the car is not unusual - rocks and debris chip a tiny bit and it goes from there. Salt makes it worse.

This is 6000 miles and one Chicago winter (I've had the car almost a year now.)

http://eldamar.net/brz/image/tein-src-install.jpg

Clean it up with a wire brush and paint it with some Rust-oleum. If you want to be really thorough, drop the front of the subframe (only the two bolts need to be loosened, details can be found in the sub-frame bushing install DIY) and paint between the body and the subframe, then let it dry before torquing to spec.

I'll have a better pic later I hope, but close enough after shot...

http://eldamar.net/brz/image/tein-src-install-31.jpg

I even pondered whether I should go for some color but decided to stick with boring flat black, since I can target small spots like you've found

I realize that rust on cast iron parts is expected, but that isn't cast iron, and it was painted, so it didn't seem like the sort of part that would be expected to rust. I guess I can just mention it to them and see what they say.

I touched up a bunch of similar spots. Interested to hear what they say, I didn't even think about warranty... Plus I was already in there. :)