97 E420- was changing oil and i pulled the lower air filter housing w/ the mouth thingy sticking out to the front. but i cannot get this darn thing back in!!!! the mouth piece just won't go back into the housing in the front by the passenger headlight - plz help!!!

Make sure with filter tray out(removed), you insert the tube near radiator first.
Then cock the filter tray 90 degrees and point the mouth opening downward and line the two up as best as you can, the rotate the filter tray and they should line up okay, then push the two together and they should snap into place unless someone went psycho with them at one point and they distorted.
make sure the rubber bushings that the tray sit on are inserted into the car body(holes) first or you won't get it to lock down easily.

thanks - i did exactly what you mention earlier this morning and got it back into place!

If you decide to take it out again (since you are a pro at it now) wash it in the sink with some good soap. You will scour out more black dust than you can imagine. Then, put some good plastic/rubber conditioner on the flexible hose from the intake vent. Mine was so dry it had pulled back from the vent, and by conditioning it, it became pliable enough to pull all the way over the vent. I was probably sucking in some hot engine bay air before.

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former: 83 300D, 97 C230, 93 400E

current: 08 C300 Luxury , 92 500SL