New G-05 hybrid coolant made by Prestone for Daimler Chrysler and Ford is compatible with the standard Green anti-freeze. This antifreeze is yellow in color and should state that it meets ASTM D6210 specifications on the label.
However if you add DEX-COOL to standard ethylene glycol green antifreeze you could be creating a problem. DEX-COOL is also an ethylene glycol based coolant, but the anti corrosion chemistry is allot different. Laboratories have proven that by mixing DEX-COOL with conventional green coolant it accelerates its ability to corrode aluminum.
I can’t find good test data to show exactly why DEX-COOL turns to sludge. It appears that introducing air into a DEX-COOL cooling system does vicious things to the coolant. For example a failed radiator cap, or a leaking intake gaskets allows entrained air to contaminate the coolant system, and then it turns to sludge.
Now would be a good time to review your cooling system and determine why you are low. Start by performing a coolant pressure test on the system to find the leak and don’t forget to test the radiator cap.
Finally, DEX-COOL doesn’t have any green tint in it.