1998 Ford Expedition Owner Guide 1st Printing - Page 162

Maintenance and care 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. What you should know about fail-safe cooling If the engine coolant supply is depleted, this feature allows the vehicle to be driven temporarily before incremental component damage is incurred. The "fail safe" distance depends on ambient temperatures, vehicle load and terrain. How fail-safe cooling works If the engine overheats, the engine will automatically switch from eight to alternating four cylinder operation. Each disabled cylinder acts as an air pump and cools the engine. When this occurs, the engine coolant temperature gauge will move into the red area and the light illuminates. The check engine light will illuminate, indicating that vehicle service is required. The vehicle will still operate, but will have limited engine power and 162 H TEMP C