FORD 2011 Explorer v.1 - Manual (Page 386)

Note: Electrical or electronic accessories added to the vehicle may
adversely affect battery performance and durability and may also affect
the performance of other electrical systems in the vehicle.
When a battery replacement is required, the battery should only be
replaced with a Ford recommended replacement battery that matches
the electrical requirements of the vehicle.
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.
Coolant concentration testing is possible with a hydrometer or antifreeze
tester. The level of coolant should be maintained 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:
• Improved freeze protection
• Improved boiling protection
• Protection against rust and other forms of corrosion.
• Enables calibrated gauges to work properly.
When the engine is cold, check the level of the engine coolant in the
reservoir.
The engine coolant should be within
the COLD FILL RANGE as listed on
the engine coolant reservoir.
Refer to scheduled maintenance information for service interval
schedules.
Maintenance and Specifications
385
2011 Explorer (exp)
Owners Guide, 1st Printing
USA (fus)