Today I changed the air filter of W126 1990 300SEL.
I now have extra parts and no clue where they go. This was supposed to be a Simple Job!

Viewing the engine from the front of the car, on the left side coming out of the air filter holder is a short hose, maybe about 3/4", that is clamped to a nipple. No problem there.

But also coming from the same place is a length of about 5" of thin white (yellow with age) tubing, looks thin like like a mediacl catheter. One end is by the filter holder or the short thick rubber hose (it's late and I can't remember), but the other end just dangles - what does it attach to?
A picture would be WONDERFUL but an explanation in words will of course also help.

AND lying in the same area I found a small black threaded cap about 1/2" tall and maybe 3/8" inside diameter. It looks like it should screw onto a threaded nipple somewhere to the left of the air filter cover but I don't see anywhere for it to go.

Would appreciate any help on this!!!

Thank you.