Is what it sounds like to me .

Before fooling with leaky O-Rings , I'd replace the obviously clogged intake screen as it should never be blkack inside .

This is why Mercedes specifies using the clear ones , so you can see the buildup of debris & crud before you give it a high speed run and suck more crud from the tank in and it clogs, reducing power and causing shaking @ idle

If you'd ruined the engine you'd know by now : it'd be smoking out the tailpipe to beat the band and also pissing oil out of every joint ~ your pix clearly show a clean & dry OM617 engine , thus it's not bad .

Relax and take it step by step , not changing parts & O-Rings willy - nilly .

Diesel 911 is your freind here .

__________________
-Nate
1982 240D 408,XXX miles
Ignorance is the mother of suspicion and fear is the father

I did then what I knew how to do ~ now that I know better I do better