1998 ML320 -- it does not have the red cap that I read about in some other threads. There is a black cap that reads:
"A140 270 00 91 MB WORKSHOP ONLY"

What gives?

Plus, instead of a 27mm nut on the crankshaft pulley, there is a retainer nut with a hexagonal central opening meant for an Allen key. The size of the hexagonal opening looks large (~14mm) but I am not sure. Anyone else run into this?

Thanks in advance.