Water… Distilled? Purified? Hose??

Mattax said
Keep in mind that a Chrysler cooling system is an open system

Assuming you have the OEM correct cap.

There are caps (I have one) that does not hang open, so it starts to pressurize as soon as the coolant starts to heat and expand.

Personally I don't like waiting till my antifreeze is at the point of localized vaporizing before it start pressurizing the system.