1996 Ford Mustang Owner's Manual - Page 249

5. Stand away from the radiator opening. Hot steam may blow out or hot engine coolant may even splash out. To find out how much engine coolant mixture your vehicle's coolant system can hold, see Refill capacities for fluids in the Index. Add engine coolant only to the reservoir. If the coolant level is low, add a 50/50 or appropriate mixture of water and the type of engine coolant that Ford specifies. You may add water by itself only in an emergency, but you should replace it with a 50/50 or appropriate mixture as soon as possible. Have your dealer check the engine cooling system for leaks if you have to add more than a quart (liter) of engine coolant more than once a month. Ford Premium Cooling System Fluid is an optimized formula that will protect all metals and rubber elastomers used in Ford engines for four years or 50,000 miles (80,000 km). It is not necessary and not recommended to use supplemental coolant additives in your gasoline powered vehicle. These additives may harm your engine cooling system. Follow the recommended service interval for changing your engine coolant. NOTE: When you change or add engine coolant, it is important to maintain your engine coolant concentration between 40% (-11˚F [-24˚C]) and 60% (-62˚F [-52˚C]), depending on your local climate conditions. Below 40% you will lose freeze protection and above 60% your engine may overheat on a warm day. 255