WARNING: This page is about a different car, the 2009 Mercedes-Benz CLK350 and 2008 Mercedes-Benz CLK350. However, it is still accessible from the selected car via links, so may be relevant.
FG 05/Set C
ENGINE 611, 612, 613, 647, 648
Use:
Retaining device for timing chain on chain sprocket for drawing timing chain into the engine