Quote Originally Posted by Canadian Cowboy View Post
There is nothing wrong with Dexcool coolant,the issue first arose with head gasket leaks,the molecules are smaller and will leak whereas the traditional green coolant will not.
Manufactures had to redesign head gaskets and head/engine block finishes to prevent leakage.
They have finally corrected it for the most part.
CC
The traditional green dyed coolant and the newer Dex-Cool are both formulated using an ethylene glycol base. Aside from the dye color, the difference is really more about the corrosion inhibitors. Dex-Cool uses carboxylate corrosion inhibitors and green dyed coolant uses silicate corrosion inhibitors. I don't know about molecule size for the corrosion inhibitors, but ethylene glycol is ethylene glycol and water is water (in these 50/50 mix ratios).

Aside from metal(s) deterioration related to coolant, gasket deterioration is also something to consider. I saw a lot of it in the late 1980s through the 1990s with the 6.2/6.5 diesels that were equipped with the green coolant. Head gaskets for the 6.2/6.5 have definitely improved through the years and for a variety of reasons, but it's the water pump gaskets and other wet gaskets that I saw deteriorate (that had the green coolant) back in the day. I just don't see it with Dex-Cool.
Jim