Okay, I've been searching not just this site, but the whole web and I can't find an answer to this question.

Yesterday, I had to take the engine cover off in order to access the vacuum lines. In doing so, I had to take off the oil cap.

After I pulled the cap off, I noticed a chunk of the plastic treading was missing. It's about the size of a thumb nail. My guess is it's INSIDE the valve cover and oil, but I'm not positive of that. What do I do?

Should I replace the oil cap? The piece that's missing is near the very bottom of the treading, so I can't see how any oil would leak. But more importantly, without knowing if that small piece of plastic is floating in the oil, what should I do?

I guess this is what you get when you buy a 13 year old car