FLEETGUARD COOLANTS CC2746 (6 PCS/BOX) 50/50 Premix Heavy Duty Coolant Fleetcool EX is a Life-of-the-Engine 1,000,000-mile coolant. Fleetcool EX is a heavy duty, extended life coolant that does not require an SCA pre--charge. For cooling system top off, simply use Fleetcool EX premix. Do not add water.