My '82 300CD had a conventional shallow, circular air cleaner,
offset to the right side of the engine right above the turbo-
charger.  My '85 300D had a different arrangement: a deep,
cylindrical air cleaner located in the forward, right-hand
corner of the engine bay.  I figured the change had been made
at some point between the 1982 and 1985 model years.

Yesterday a friend of mine purchased an '85 300D, and it has
the same wide, shallow air cleaner housing that my 1982 car
had.  

My friend is new to Mercedes ownership, and in order to spare
him the hassle of getting the wrong part when buying a new air
cleaner element, I wanted to find out how typical his car's
set-up is.  (The first time I bought a new element for my '85,
I was given the tall, cylindrical one, no questions asked.)

Was there a running change in air cleaner design during the 1985
model year?  Or is it likely that his car had the earlier part
fitted at some point after it was originally purchased?

Geoff