Rust inside oil cap?

[fennsz]

I was changing oil on my brother-in-laws suburban with the 5.3L and I notice that inside on the underside of the oil cap it looked to be rust and condensation. I haven't noticed this on my Z and was wondering if I should be concerned about it?

[RyanbabZ71]

Rust?  Isnt is a plastic cap?  I have noticed a slight amount of condesation in mine since new

[fennsz]

that's what I thought, but I rub to get it out and most came out, but it really looks like rust for some reason? I don't know, some I couldn't get out, I can try some solvent on it and it will work to take it off I think?

[Shaners]

Does your Bro-in-law do alot of short trips?  It seems like he probably does since there is condensation and build-up inside the oil filler cap.

[fennsz]

yep, it's actually his wife's truck. take the kids to school and back every morning and a little run around shopping. That's about it. Soccer mom.

[GnatGoSplat]

It's probably motor oil varnish.  Most of it should come out with lacquer thinner.

[Tweeter400]

My truck had the same thing, it was just oil residue, but it sure looked like rust!

[BlueRado]

Hate to sound like the dealer service dept, but in this case, it is "normal".    The rust colored residue, I mean, most noticeable w/ lots of short trips.  

[fennsz]

thanks everyone...my worries are over. I will just clean it out.