[V8] Coolant type?

[toml99 at todomundo.com]

My 04 Duramax still has about a year on the powertrain warranty, so I  
was forced to refill with the Dex-Cool recently.  When that's up, I  
will probably flush it out and use something different, as there's a  
lot of bad press about the Dex-cool.  Since I've always used the Audi/ 
Vw  Blue in the Audi's, I may consider it, but it holds gallons, so  
may go with something else, but it definatly, won't be green.  Most  
of the problems associated with the green are from steel blocks with  
aluminum heads, and that set's up an electrolytic reaction that will  
pick away at the aluminum.  I just did the head gasket + in the  
girlfriend's 91 Toyota truck, and the head gasket(aluminum) was swiss  
cheese around the coolant ports), as the Toyota Red was replaced by  
the green at some point, years ago(steel block/aluminum head)and the  
Toyota mechanic say's he see's it all the time.  If I'm not mistaken,  
the Febi waterpump for our cars, used a steel impeller....Will that  
create a charge in the coolant? Not sure.  Years ago, a mechanic  
friend showed me an aluminum head off something he was working on,  
and the head and gasket was swiss cheese also.....he put a voltmeter  
in the radiator, and it registered 1.2V with the battery  
disconnected....The coolant system/engine had become a battery, which  
electrolytically removed the aluminum.  Not the case with the Audi  
blue/MB or Toyota red......That's my $.02....Sincerely, Tom