I just had a situation where I needed to add some coolant and I was changing the coolant filter. My 2003 ISL 400 CM554 needs coolant meeting Cummins Engineering Standard (CES) 14439 to prevent cavitation. Cummins support mentioned earlier years cavitation was a bigger issue than newer engines. My issue was my coolant looked newer and was likely changed a year or two before I bought the coach in 2024, so I didn't want to change coolant not to mention the hassle. But, the color was green and I wanted to stick with green to monitor the condition of the system and not mix up types of coolant. Cummins sent me a list of approved coolants and only a few were green in color. For what it is worth I'm sharing in case it is helpful for anyone in the future.
Unless standards have changed on the green coolant it requires additives and the ability to check how much is needed when used. I still have a refractor and some out dated test strips I need to get rid of from my time with the '96 Monaco.