Ok. If we’re done with the Maypo. Xerex G05 was the recommended coolant for Mercedes for many years. It’s a hybrid coolant…part OAT and light silicates. It also has nitrites, which are important for Diesel motors. It’s not orange (that’s Dexcool), it’s yellow. Many Mercedes engines have similar materials to XK’s…the 60x series has iron blocks and aluminum heads, as an example. So while the truth is that you never know, G05 is my go-to for the Euro side of the shop.
The newer version of G05 is G48, which is blue, but not to be confused with Japanese coolants, which are also blue and phosphate free. One thing I don’t recommend is Dexcool, which is the orange GM stuff. This is an OAT coolant, which has been known to be problematic in old engines with existing silicate deposits.
Traditional antifreeze relied primarily on silicates. The characteristic of silicates is that they tend to fall out of solution, which is why the old coolants needed to be changed every two years.