Speaking "Ford-ese"...

DexCool is ethylene glycol based. It just has a different anticorrosion chemistry.

Regular old Prestone Antifreeze meets Ford ESE-M97B44-a (see

|Hello, | |The shop manual for my '99 Windstar calls for "Premium Engine Coolant, |E2FZ-19549-AA" meeting "Ford specification ESE-M97B44-A" | |It later offers the following cautions: | |"Caution: Do not use Extended Life Engine Coolant F6AZ-19544-A meeting |Ford specification WSS-M97B44-D(orange color)." | |and | |"Caution: Do not mix Standard (green) Coolant with Extended Life Coolant |(orange)." | |Based on the hints provided (color, words like "standard") and the |recent DexCool discussion on this list, I'm under the impression that I |should use an ethylene glycol based coolant and not the DexCool. | |Is this correct, and are there any special constraints imposed by the |Ford Spec ESE-M97B44-A

Do not assume that the orange coolant is Dex-Cool. In this case it's more likely G-05. Rex in Fort Worth

One of the reasons Ford wants you to stick with the old fashioned green stuff is that many of the long life formulations corroded the gaskets in their engines. Other problems were that the long life tend to be low silicate formulated and don't provide sufficient cavitation protection to the water pump impeller.