Can you use regular antifreeze instead of dex-cool?

Answer 1

Despite the warnings from the manufacturer, yes you can use the regular "green" antifreeze instead of Dex Cool. BUT you must have the cooling system completely and thoroughly flushed before you switch.

No. Dex Cool was designed for modern engines and has specific protection packages within the coolant to protect the cooling system and components that the old standby green coolants don't have. The older coolant was designed for early to mid 20th century engines and the Dex Cool has better ingredients to work with the various metals and other products that make up our modern 21 century engines. The trick to getting the best performance from your Dex Cool with the fewest issues is preventative maintenance. Make sure the level is always full, keep air from getting into the system, DO NOT mix with other coolants, and replace every 3 years/50,000 regardless of what it says on the bottle. One can never remove ALL of the old coolant during a flush so recommending a "complete flush" before switching is useless. Any traces of the old coolant will cause issues with the new, so stick with the DexCool and just maintain it properly.

Example: My dads 1996 Monte Carlo required dexcool. He added the green antifreeze instead and his engine died about two weeks later. Once the motor was changed and the coolant flushed, all he used was green and hasn't had a problem since. It is not a good idea to mix the green with the dexcool! If all the dexcool is out of the system and only the green is used then it works fine.