Zerex G 05 antifreeze isn't "approved" per se by Mercedes Benz. We're starting to mince words here.
Here are a few quotes from the Zerex web site:
"Approved by Ford and DaimlerChrysler for use in automotive and diesel engines. "
"Zerex G 05 antifreeze coolant meets or exceeds the performance requirements of the following antifreeze specifications and/or recommended practices: ..... Mercedes Benz Approved...."
I personally believe Mercedes hasn't approved Zerex G 05 as a business practice - not for technical reasons. They are interested in selling their own aftermarket products at inflated prices. Conversely, Zerex can't say their product is approved by MB. Zerex can only state that their product meets (or exceeds) the requirements for MB antifreeze specification. I still say Zerex G 05 is okay to use in MB engines.
95 E320 Cabriolet, 131K