I've used the G-05 coolant since purchasing the 95 E300D several years ago. I do add a small bottle of ultraviolet light traceable dye to help find coolant leaks. I check for those about every three months.

This pdf says that G-05 is still ok to use. What is the benefit of changing & what is the latest best?

https://www.mbca.org/sites/default/files/antifreedec04_0.pdf