After 5 years the coolent will cause corrosion, and could start to clog the radiator. MB specs better maintaince standards because they don't want their cars to wear out, they are supposed to last 20+ years. Thats the reason the spec out brake fluid changes every 2 years. MB coolent is $9 a gallon threw Fastlane and is chemicaly different then other coolents. Will you car blow up if you use the green stuff? No but your radiator will go south faster, plus your head gasket won't like it. Thats $500 in parts on my car. Not to mention resale, If I see green coolent in a MB I look at I want to knock the price down.

__________________
2006 CL500
2009 C300 4matic
1969 280SE
2023 Ram 1500
2007 Tiara 3200