[DeTomaso] alum heads on the street

[dyogi at hawaii.rr.com]

I got a crash course on coolant systems when I took the No-Rosion distributorship in Hawaii.  Plain water is the best coolant as far as temperature transfer is concerned.  Anti freeze provides corrosion protection but has two drawbacks.  One is that it loweres the temperature absorbtion rate by about 50% when used as a 50/50 mix.  Another is it contains silicates that act like micorscopic sand paper that eats away at seals and softer aluminum.  It didn't affect iron blocks and heads much but now with much of the engines made of aluminum, it has become an issue.  

Extended life antifreezes such as Dexcool was developed to eliminate the silicate problem with today's modern engines but its draw back is that it is easily contaminated and turns to a brown gel clogging the cooling system.  Annodes work to an extent but tend to be localized and not cover the entire cooling system.  In addition, many people use zinc annodes available at boating stores in their cooling system which are made of zinc.  Zinc annodes do nothing if used with fresh water systems as it works against salt water. This is why they are used on external boat parts such as outboards, legs, and rudders.  The correct annode to use with fresh water systems are made of magnesium.  This is what has been explained to me, if I am incorrect on any point, please chime in and correct me.

Aloha From Hawaii,

Dennis