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Old 12-10-2002, 09:15 AM
Kestas Kestas is offline
I told you so!
Join Date: Jun 2002
Location: Motor City, MI
Posts: 2,804
Originally posted by Ken Downing
One thing that I have learned about Coolent is that the green stuff.. has silica in it.... Thats a fine sand so to say.. It helps polish the inside and keep it clean.. No I can not feel it
Just to clear up any misconceptions, the silica in glycol coolants is in the form of sodium silicate (water glass), not silicon oxide (sand). The sodium silicate plates from solution onto the water jacket surfaces, thus protecting the surface from corrosion. That's why a properly maintained cooling system looks clean and shiny.

I've been paid good money by the automotive manufacturers to look at issues involving sodium silicate. I've examined it in the lab using microscopy methods, and can tell you it is not nearly as abrasive as sand. In fact, it has a consistancy more like talc, which is so soft, under some conditions it is sometimes considered a solid lubricant.

Data shows glycol coolant loses its corrosion protection after 30,000 miles. That's why regular coolant changes are so important.

I don't know if MBZ dealer coolant has sodium silicate. I'll check the jugs in my basement to see if it's listed as an ingredient.
95 E320 Cabriolet, 140K
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