Grade / weight doesn't matter. You just need to look for something meeting MB spec 229.51.

Here's a list stolen from another site:

Rowe Hightec Synt RS DLS 5w30
Total INEO MC3 5w30
OEM Mercedes-Benz fully-synthetic 5w30 oil
Pentosin HP2 5w40 - higher viscosity than most other 229.51 oils
Liqui Moly Top Tec 4200 5w30

-J

__________________
1991 350SDL. 230,000 miles (new motor @ 150,000).

Tesla Model 3. 136,000 miles. Been to 48 states!
Past: A fleet of VW TDIs.... including a V10,a Dieselgate Passat, and 2 ECOdiesels.
2014 Cadillac ELR
2013 Fiat 500E.