If you want to boggle your mind, or just have some intense, interesting reading, there is plenty about antifreeze technology. Yeah, for the most part raw (undiluted antifreeze) is more than 90% PG (propylene glycol, which is "non-toxic") or EG (toxic ethylene glycol). The balance are all the "additives" or inhibitors which include a Pandora's box of proprietary chemistry including silicates, phosphates, pH adjusters, organic acids, borates, corrosion inhibitors which include BTA, TTA...get the picture? I think most of us can be equally mystified by going to the antifreeze aisle of an AutoZone or Walmart!
Take the advice of experts...use a brand/formulation specified for our car, check your pH, change your fluids...
I'd be interested to get the part number of antifreeze from MB specified for our older engines and cooling systems...anyone?