The answer is a definite no. Ford specifically states in their manulas and maintenance guides that Motorcraft Premium Gold coolant is not to be mixed with any other type of coolant, including their own Premium Orange and Premium Extended Life Green coolants. Dex-Cool and other "Universal" orange and green coolants are not to be mixed either, as these do not contain the specified additives Ford requires for continued cooling, anti-corrosion, and seal lubricating capabilities.
Either green coolant or red ECL (extended life coolant), depending on year and make and model of engine.
Either universal green or red ELC (extended life coolant), depending on what engine it has.
The Cummins ISX uses red ELC (extended life coolant).
General Motors changed to Dexcool Extended Life coolant in 1996. It is the orange colored coolant. Green coolant will not hurt the system, it must be replaced about 5 times as frequently though. Beware that once you use green coolant in your cooling system, it is very dificult to remove completely if you want to use the extended life coolant in the future.
It is not rust, but broken down extended life coolant. When Extended life coolant goes beyond the replacement time, every five years, it can break down and turn into a rusty sludge like substance. I would bet if you haven't changed the coolant in the car, it has never been changed.
You should be using red extended life coolant (ELC).
extended life "red coolant' Tell the people at the parts store and they will get you the oem coolant (do not mix red and green)
Some examples of antifreeze brands that are phosphate-free include Zerex G-05, Prestone Extended Life Antifreeze/Coolant, and Peak Global Lifetime. It's important to always check the product label or specifications to ensure the antifreeze you are using is phosphate-free.
Dexcool, which is an extended-life coolant, should not be mixed with plain water. It is designed to be used with a specific 50/50 mixture of Dexcool and distilled water to ensure optimal performance and prevent corrosion. Mixing it with tap water or other coolants can lead to chemical reactions that may cause engine damage. Always follow the manufacturer's recommendations for coolant mixtures.
You may use Volkswagon G12 coolant or Prestone Extended Life coolant. If cost is a factor use the latter.
The 1998 Ford Ranger Owner Guide shows Ford Extended Life Engine Coolant ( Dexcool )