FORD 2010 Ranger v.1 - Manual (Page 245)

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.
• Enables calibrated gauges to work properly.
• 2.3L engine
Maintenance and Specifications
245
2010 Ranger (ran)
Owners Guide, 1st Printing
USA (fus)