Only a chemical flush will get rid of Dex-cool if you want to use a ethylene glycol based coolant . A vehicle with a coolant recovery system should never use Dex-Cool because exposure to air will turn it into orange mud. Dex-cool uses OAT (Organic Acid Technology) instead of ethylene glycol silicates as rust inhibitors and just like any coolant, it should be changed every two years or every 20,000 miles, especially if it is Dex-cool.
After my 1991 S-10 Blazer 4x4 was purchased in the fall of 1991, I have used Prestone anti-freeze concentrate diluted with a gallon of distilled water and I replace it every two years. The 22 year old cooling system is like new. Since it was introduced in 2006, I have used one gallon of Prestone 50/50 Anti-freeze Coolant per car and I change it every two years or less. . It is a 50-50 mix of ethylene glycol coolant and demineralized water.
A 50/50 coolant is convenient to use but you are paying double the price for half the amount of ethylene glycol coolant. Just like any other product, people must pay extra for convenience.
Last edited by MouseFink; 02-15-2013 at 06:17 AM.