There was a previous thread in the archives under "Mercedes Antifreeze" which has a lot of additional information. One point that stuck out (no pun intended), was one member's assertion that mixing high silicate and low silicate antifreeze together would clog up your cooling system.
Also, it was pointed out that MB coolant isn't actually Ethylene Glycol, it's Glysantin. Here's the direct quote from Kent Christensen's posting, along with the links he provided:
"There certainly is a difference between MB antifreeze and anything green. Mercedes antifreeze is Glysantin. See the following articles: http://www.imcool.com/articles/antifreeze-coolant/G05-Glysantin.htm http://www.valvoline.com/products/cooling/technicalbulletin/tb_zerex_antifreeze.html"
I might also suggest that the use of distilled water added to the coolant instead of water from your garden hose would reduce, if not totally eliminate the formation of scale in the cooling system due to it being free of any minerals, unlike tap water, which can contain a wide variance of minerals and contaminants depending upon your local water supply.
And, CJ, it seems to me that you aren't getting any coolant circulating into your heater core?
[Edited by longston on 01-13-2001 at 02:23 PM]