Nitros use HOAT type coolant. The yellowish green stuff they sell in the stores these days tends to be a "universal" type coolant that they claim is good for all vehicles, and can mix with all coolants. I don't know if that's true or not though. The Mopar HOAT coolant is either orange or reddish. They changed the color at some point. When I buy HOAT coolant, I just buy concentrated Zerex G05, which is light gold color, and mix it with distilled water.