1996 Mercury Mystique Owner's Manual - Page 212

RWARNING Failure to follow these instructions could result in serious personal injury from hot engine coolant or steam blowout and/or damage to the engine cooling system or engine. To find out how much engine coolant mixture your vehicle's coolant system can hold, see Refill capacities for fluids in the Index. Have your dealer check the engine cooling system for leaks if you have to add a quart (liter) of engine coolant more than once a month. Add engine coolant only to the recovery reservoir. If the coolant level is low, add to the reservoir a 50/50 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 mixture as soon as possible. Check the engine coolant again the next few times you drive your vehicle. 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 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. 216