See this thread.

http://www.peachparts.com/shopforum/showthread.php?t=164454

M.B. coolant has the correct chemical composition to protect the aluminum, plastic and rubber components of the cooling system.

I used a red Hoat in my M103 for a few months. Flushed it out and changed it to original MB (Lemforder) Blue stuff.

The red HOAT "seemed" to weep out of connections. No problems with the Lemforder Blue.

Last year I suffered the Mercedes W124 broken radiator plastic neck problem. That's why I changed out the coolants in the first place. The red Hoat I installed and then later removed was claimed to be up top M.B. standards.