1989 Ford Bronco Owner's Manual - Page 280

Maintenance and Specifications ENGINE COOLANT Checking engine coolant The concentration and level of engine coolant should be checked at the intervals listed in scheduled maintenance information. The coolant concentration should be maintained at 50/50 coolant and distilled water, which equates to a freeze point of -34°F (-36°C). Coolant concentration testing is possible with a hydrometer or antifreeze tester. The level of coolant should be maintained at the FULL COLD level or within the COLD FILL RANGE in the coolant reservoir. If the level falls below, add coolant per the instructions in the Adding engine coolant section. Your vehicle was factory-filled with a 50/50 engine coolant and water concentration. If the concentration of coolant falls below 40% or above 60%, the engine parts could become damaged or not work properly. A 50/50 mixture of coolant and water provides the following: • Freeze protection down to -34°F (-36°C). • Boiling protection up to 265°F (129°C). • Protection against rust and other forms of corrosion. • Proper function of calibrated gauges. When the engine is cold, check the level of the engine coolant in the reservoir. • The engine coolant should be at the FULL COLD level or within the COLD FILL RANGE as listed on the engine coolant reservoir (depending upon application). 280 2010 Econoline (eco) Owners Guide, 3rd Printing USA (fus)