Hmm! Id like to see the proof of it erroding the seals. It seems suspicious that only one family of engines has the same gasket blow and none of the other gm cars, trucks, and newer vans have no problem, and continue to use dex cool. And shockingly enough, gm comes out with a revised seal.
As well, some Sterling (Freightliner), MACK, and One or two Chryslers use Dex-cool, and you would be hard pressed to find any complaints about it.
Heres some reading to bolster the concept. Also I have yet to see any class action suit against dex cool winning. I have seen about the gaskets winning.
http://www.imcool.com/articles/antif...l-macs2001.htm
HOWEVER.
5 years, 240,000kms. Right. Anyone who can do a web search can see tons and tons of lawsuits and other issues. Dex-cool IMO cannot survive this long.
http://www.autoblog.com/2006/05/23/g...action-status/
The fellas here at autoblog have inidicated that it can, providing that you keep up with the most stringent maintenance, do not add tap water, yadda yadda yadda. Gm made us a promise. And I doubt if the general can keep it.
Myself, I go by the eyeball method. If I look in the rad and overflow and it looks dirty, I change it. Simple.