1997 Mercury Cougar Owner's Manual - Page 217
1997 Mercury Cougar Manual
Page 217 highlights
Severe winter climate If you drive in extremely cold climates (less than -34˚F [-36˚C]), it may be necessary to increase the coolant concentration above 50%. Refer to the chart on the coolant container to ensure the coolant concentration in your vehicle is such that the coolant will not freeze at the temperature level in which you drive during winter months. Never increase the engine coolant concentration above 60%. Leave a 50/50 mixture of engine coolant and water in your vehicle year-round in non-extreme climates. Engine Coolant Drain and Flush Proper procedures for a complete coolant drain and flush of the cooling system can be found in the Car Service Manual. Following these recommended procedures will ensure that the specified coolant level and a 50/50 or appropriate mixture of coolant and water is maintained. Engine Coolant Refill Procedure When the entire cooling system is drained and refilled, the following procedure should be used to ensure a complete fill: NOTE: It is imperative the following procedure be adhered to. Failure to do so could result in damage to your engine. 217