OM603 - I believe he mentioned that the instructions suggest installation with the expander and another option without the expander. 2 separate installation options for this oil ring.

AHKay - certainly, you have your own opinion about what is reasonable and practical for every application and their limits. This being a case where an unknown manufacturer has designated this the proper part for your application - seems good enough to suffice. On the other hand, it is not as desirable as the 3 piece OE part designated by MB.

I would install without the expander if I was in a tight spot, but prefer to contact the supplier or manufacturer or buy an OE set that had the coil spring expander.

I would ABSOLUTELY check ring end gap before installing this ring on the piston!!!!

And ring clearance!!!

Regardless of their quality and reputation, non-european parts suppliers have often left me unsatisfied when it come to Mercedes and the like - too many failed items and bad fitments that I have witnessed personally (I am not a seasoned professional, and that is limited experience, but a pattern exists)

Regardless, I am very suspect regarding this ring, but certain you could make it work if it is the proper part sold by the retailer.

__________________