Look what I found under the valve cover.
 

So I took the valve cover off of my 300SD to do the first valve adjustment on the car since I bought it last month. This plastic ring was just sitting there next to the timing chain guide. The engine runs very well with no suspicious clicking or knocking. Does this look like something that just fell in there during the last valve adjustment by a careless mechanic or something worse? Praying for the former.

Looks like one of those rings under the cap on a gallon oil jug to me. Hope I'm wrong.

looks like the plastic seal on a bottle of oil to me...

Looks like who ever changed the oil was not too careful. Interesting that it found its way there. Just as well it wasnt a metal lid or something else.

Looks like a lucky shot. It's an oil cap security ring, the kind that breaks off to let you know it's been tampered with. Someone probably jammed the bottle in the filler hole and didn't pay too much attention when they pulled it out.

I found a large flat head screwdriver I left next to the windshield washer bottle about a week after I did my coolant change :o

And when I went to Bill's GTG back in August, I found my quarter inch socket extension in the rubber fold that seals the hood.

I don't keep any detachable small tools near me when I do my valve adjustments :P

It could have been next to the cover and upon removal fallen in. I had a dead moth inside my cover, took me a second to realize it simply fell in since it was resting on the cover.

But its probably as other said, someone jamming the oil bottle in there and it falling off upon removal. Just be glad you found it where you did!

IMHO it couldn't have done much damage, if caught in the chain it would have been pulverized, its just a piece of cheap plastic. And, if it had gone lower it would have ended up laying in the pan or stuck to the oil instake screen. Probably not a lot of risk overall....good thing you found it though! :eek: