Coolant Fluid
Cooling Fluid, or more generally "Coolant" is typically used to cool down the temperature of surfaces where the coolant is sprayed due to the cryogenic properties of the liquid. While it is not intended for firefighting, it can be used for when Flame Retardant Foam is unavailable.
It is typically carried in Coolant Trucks, and can be used to assist an overheating 'Mech to cool down.
It can be used in the common Fluid Guns and Fluid Sprayers, as well as the Vehicular Flamer.
A spray from coolant to the outside of a 'Mech can bring down the heat level of a 'Mech by 3 using the Classic BattleTech Heat Scale.
Coolant Fluids can also be directly exchanged via a coolant truck in the event that the 'Mech overheats. While the coolant used in a 'Mech is very effective, it will "wear out" eventually and need to be replaced, especially if intense heat loads are applied to the cooling system.