Found during oil change

[zuluwiz]

I used to keep those on hand when changing oil filters, would pop at least one every time. It's amazing the stuff you get used to doing and don't even think about.

(edit)Checking back with the Original Post, I see that the piece wasn't found inside the engine, which is a relief. I really need to slow down and read it all. Anyway, that's an easy fix, nothing internal. I'm thinking the reason those tops come off is that the thin metal washer that is supposed to be under the nut gets lost and the person doing the changing (that would be me) doesn't notice and puts the nut back on without it, then overtightens. Easy mistake, get in a hurry to finish, then wonder why oil seeps past the threads.

[LAB3]

I used to keep those on hand when changing oil filters, would pop at least one every time. It's amazing the stuff you get used to doing and don't even think about.

(edit)Checking back with the Original Post, I see that the piece wasn't found inside the engine, which is a relief. I really need to slow down and read it all. Anyway, that's an easy fix, nothing internal. I'm thinking the reason those tops come off is that the thin metal washer that is supposed to be under the nut gets lost and the person doing the changing (that would be me) doesn't notice and puts the nut back on without it, then overtightens. Easy mistake, get in a hurry to finish, then wonder why oil seeps past the threads.

Don't feel bad, I had a perplexing oil leak that turned out to be a missing copper oil plug gasket that I lost the last time I changed it. Cheapo me goes and gets a nylon one at the hardware store that lasted til about 500 miles shy of the next change.

[Suzukian]

So it fell into the oil pan during an oil change. Wow, what a relief!! Goes to show you have to be meticulous about oil changes and look for the smallest things. I can imagine now you're going to have an Eagle eye!

[rphillips]

I's like zulu, I thought it came out of your "oil" pan, reread and realized came out of "catch" pan.... Glad it got sorted out.

[XLNDRVR]

I's like zulu, I thought it came out of your "oil" pan, reread and realized came out of "catch" pan.... Glad it got sorted out.

Yes, found it when draining the catch pan into an oil recycling jug. Got concerned and posted before looking the engine over. I hadn’t realized there was anything out of the ordinary when re-installing the filter cover. When I figured it out, I felt silly for raising the question.

[Rich82GS750TZ]

It's all good. I hadn't seen this issue posted before. So it's either not very common, or nobody has ever reported finding the dome of one of the oil filter cover acorn nuts sheared off. It had enough of us scratching our heads to make raising the question worthwhile.

[Grimly]

I suspect a lot of the acorn nuts lost their tops years ago or were simply replaced with ordinary nuts.
There haven't been chrome tops on mine for a long time.