your question gets me thinking of axing that cover completely. I think the air intake pipe is screwed on to it but the arrangement is not stuck in my head. I experienced the same thing on my 97 E320. I already axed that other cover over the fuel injectors and I am this close to getting rid of the front cover with the star after it dislodged one day and was getting chewed by the fan. Anyone have any objections to getting rid of the coil cover? Coils are not being cooked and maintenance is much easier. (By the way was your cylinder #6 plug oily?)